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The super-aggregated AmB can thus be used to improve the therapeutic index of AmB against a plethora of fungal infections including candidiasis and ...

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Super Aggregated form of Amphotericin B: A Novel Way to Increase its Therapeutic Index Qamar Zia1,2,*, Asim Azhar1, Mohammad Amjad Kamal3,4, Gjumrakch Aliev5,6,7, Mohammad Owais1 and Ghulam Md Ashraf 3,* 1

Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India; Department of Biotechnology, Gagan College of Management and Technology, Aligarh, India; 3King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia; 4Enzymoic, Hebersham, NSW, Australia; 5GALLY International Biomedical Research Consulting LLC., 7733 Louis Pasteur Drive, #330, San Antonio, TX, 78229, USA; 6School of Health Science and Healthcare Administration, University of Atlanta, E. Johns Crossing, #175, Johns Creek, GA, USA 30097; 7Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432, Russia 2

Qamar Zia

Ghulam Md Ashraf

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Abstract: Amphotericin B (AmB)-deoxycholate micellar formulation, Fungizone®, is the drug of choice for the treatment of unidentified mycotic infections. However, it usage has been marred by long therapeutic regimes and severe side effects. The less toxic lipid associated AmB formulations have been limited by their high expense, with some loss in activity. The quest for decreasing AmB cytotoxicity as well as production cost has resulted in the development of AmB super-aggregate as an alternative to its existing lipid formulations. AmB super-aggregate is spectroscopically distinct from the aggregate present in Fungizone, displaying enhanced thermodynamic stability. The poly-aggregated form of AmB exhibits reduced toxicity in mammalian cells in vitro and to mice in vivo, while maintaining its ‘gold standard’ antifungal activity. Poly-aggregated AmB interacts predominantly with serum albumin and also attenuates its ability to induce potentially harmful cytokines. Bio-distribution studies have demonstrated that the selfassociated AmB shows greater accumulation in reticulo-endothelial organs while sparing kidney, one of the principal organs where its toxic effects are seen. The super-aggregated AmB can thus be used to improve the therapeutic index of AmB against a plethora of fungal infections including candidiasis and cryptococcosis, thus providing a fitting solution to growing demand of an active, less toxic substitute of AmB.

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temperature [19-23], AmB molecules can remain freely separated in true solutions or self-associate to build up macromolecular structures [24-28]. At least three different aggregation states of AmB have been catalogued by authors. In organic solvents, AmB is obviously present in monomeric form. In the conventional FZ preparation, AmB adopts an oligomer form (soluble aggregates). However, in aqueous milieu, AmB is usually present as a mixture in equilibrium of monomers and soluble (oligomers) and non-soluble aggregates (poly-aggregates). The concentrations of each species depend not only on the total AmB concentration but also on the concentration of the AmB in stock solutions [19, 22]. The toxic and chemotherapeutic effects in mice were demonstrated to be correlated to the aggregation state [29] and to the particle size of intravenous AmB [30]. The equilibrium between monomers and aggregates seems to play a key role in drug activity. The monomeric form binds to ergosterol in the fungal membranes and form pores, whereas the self-associated oligomeric form leads to the formation of transmembrane channels through the cholesterol-containing membranes. Moreover, the aggregation state of AmB greatly influences the selectivity of the activity of AmB against ergosterol-containing fungal cells with respect to the toxicity against cholesterol-containing mammalian cells [20, 22, 25, 31]. Self-associated soluble form of AmB was shown to increase the permeability of cholesterol-containing egg phosphatidyl choline vesicles to K+, while both the monomeric and the aggregated forms of AmB modified this parameter in ergosterol-containing liposomes [31, 32]. Different types of aggregation of oligomers or poly-aggregates can be obtained by heating FZ [19], by interactions with different

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INTRODUCTION The conventional Amphotericin B (AmB)-deoxycholate micellar formulation, Fungizone® (FZ) is the most widely used drug for the treatment of deep-seated mycotic infections, commonly found in immunocompromised hosts (e.g., individuals with AIDS), cancer patients and diabetics [1-8]. However, a wide variety of acute and chronic side effects such as anaphylaxis, chills, high fever, nausea; of which nephrotoxicity is the major adverse effect [9]; has limited the daily dose of FZ to ~1 mg/kg. This array of untoward effects coupled with long therapeutic regimes nearly negates its usefulness in all but the most life-threatening systemic fungal infections [6]. It led to the development of less-toxic liposomal and lipid-associated AmB formulations (e.g., AmBisome, Abelcet, also known as AmB lipid complex [ABLC], and Amphocil). Although these lipid carriers proved to partially reduce AmB-induced toxic manifestations [10-16], their usage has been limited by their high expense. Moreover, these new formulations are not as potent as the conventional AmB on an mg/kg basis; often requiring high dosages to be effective for treatment [17, 18]. Due to its structural feature (Fig. 1), amphiphilic AmB is poorly soluble in water and can adopt several different organizations. Depending on various parameters such as medium, excipients and

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Keywords: Amphotericin B, bio-distribution, spectroscopy, super-aggregate, toxicity.

*Address correspondence to these authors at the Department of Biotechnology, Gagan College of Management and Technology, Aligarh, India Aligarh, India; Tel: +917417775657; E-mail: [email protected] King Fahd Medical Research Center, King Abdulaziz University, P. O. Box 80216, Jeddah 21589, Saudi Arabia; Tel: +966593594931; E-mails: [email protected], [email protected]

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© 2016 Bentham Science Publishers

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Fig. (1). Structure of AmB depicting its amphiphilic nature.

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maximum at 322 nm [19]. These two maxima (339 and 322 nm) has been suggested to correspond to pure electronic transitions [19]. The absorption spectrum of the solution remained unchanged for temperatures higher than 70°C [19]. One minor absorption peak ca 420 nm also appear along with a shoulder at around 390 nm. After a 20-min heating and cooling, an increase in the size of aggregates up to flocculation occurs, as suggested from the increase in the Rayleigh scattered light [19]. The opalescence of this heated solution can be eliminated by centrifugation. Cryo-transmission electron microscopy revealed thread-like, aggregated micelles for FZ (~4 nm in diameter) and pleiomorphic cobweb structure for HAmB, with mean particle size of ~300 nm, as determined by laser diffraction studies [39]. Only a very small fraction of the suspension (less than 5%) consists of much larger aggregates (particle sizes of 10 to 30 m) [39]. In an aqueous solution at 70°C, the apparent mass of the aggregate was 500-fold larger than the one at 20°C [19]. Therefore, the term super-aggregate used for this new species of AmB is completely justified [19]. AmB fluorescence is sensitive to different aggregation states. Recently, the detection of monomeric AmB and dimeric AmB was described employing fluorescence spectroscopy [43]. The authors reported that excitation at 350 nm excites the AmB dimer while 408 nm light stimulates the AmB monomer. Excitation of higher aggregates has been suggested to occur at 325 nm. The fluorescence excitation and emission spectra of H-AmB at 408 and 350 nm were very similar to those of FZ but with increased intensity [44]. This increased emission intensity for monomeric form of H-AmB was unexpected but agrees well with Gaboriau’s finding of slightly increased monomeric AmB content after heating [19]. Moreover, they argued that increased emission intensity for dimeric AmB excitation may be related to a change in quantum yield for the fluorescence process. Fluorescence emission of AmB as FZ and H-AmB when exciting higher aggregates of AmB at 325 nm shows identically those bands that were observed for FZ and H-AmB fluorescence under 350 nm excitation. However, the fluorescence emission intensity for FZ increased by 26% relative to that of 350 nm excitation, and this increase was nearly constant across the spectrum. HAmB excited at 325 nm shows an approximately 10% increase relative to that of 350 nm, but this increase was only in the range of 450-540 nm [44]. Aggregation-induced spectral shifts for AmB absorbance and fluorescence may be rationalized via exciton theory [45]. Fluorescence emission resulting from de-excitation of the S2 (11Bu) and the S1 (21Ag) energy states is typical for polyenes characterized by the conjugated double bond system n=7 [46-50]. Emission band, assigned to the S1  S0 transition is not homogeneous, either due to possible overlap of different electronic energy levels of monomeric AmB or due to the presence of different molecular organizational forms in the sample. In the case of monomeric fluorophores, emis-

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SUPER-AGGREGATED FORM OF AmB IS SPECTROSCOPICALLY DISTINCT FROM AGGREGATE PRESENT IN FZ As a potentially simple and cost-effective alternative, AmB or FZ solutions can be treated with moderate heat (70°C for 20 min) to produce a highly self-associated state of AmB, the “superaggregate”, referred to as heat treated AmB (H-AmB) [19, 42]. This new self-associated form of AmB is spectroscopically different from FZ, with a blue-shifted absorption maximum, a unique circular dichroism (CD) spectrum, and pleiomorphic cobweb-like ultrastructure [39]. In order to prepare H-AmB, millimolar stock solutions of FZ or AmB is diluted 10-fold with vigorous stirring in pure water or in a phosphate-buffered saline (pH 7.4). These diluted FZ or AmB solutions are then heated for 20 min at 70°C [19]. Heating (for 20 min at 70°C) and cooling the concentrated (10-4 M) solution leads to significant changes in the AmB aggregation state. This selfassociation of AmB molecules can be observed by spectroscopic studies. During the preparation, Rayleigh scattering contribution (which depends on the sizes of the aggregates) was measured in a spectral range at which AmB does not absorb (650 nm). The absorption spectrum of AmB solutions (10-4 M) before heating is characteristic of the soluble aggregated species, with a maximum centered at 339 nm [19]. Upon self-association, the characteristic polyene vibronic structure of the AmB monomer collapses to an intense blue-shifted band characteristic of some type of stacked array of interacting absorbers. Its absorption spectrum shows a new maximum located at 322 nm, instead of 339 nm [19]. An isobestic point around 328 nm, (when the temperature increases from 25°C to 70°C) suggests that the aggregated species that absorbs at 339 nm was thermally converted to new super-aggregated form with a

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excipients [33, 34] or by variations on the pH conditions during the preparation protocol [35, 36]. The different aggregated forms of AmB are associated with different stability, toxicity and efficacy profiles. It can be, therefore, said that one of the best strategy for decreasing the cytotoxicity of AmB is to develop new derivatives and/or formulations that would lead to a decrease in the level of aggregation or that would give rise to less toxic aggregates. Thus, AmB ‘super-aggregate’ has been suggested as an alternative to existing lipid formulations [37]. Recently, investigators have reported that heat treatment of FZ, induces a super-aggregated form that leads to a new equilibrium, with increase in the size of aggregated AmB. This novel formulation has been associated with reduced toxicity in mammalian cells [19, 38, 39] in vitro and to mice in vivo [39, 40] than the small soluble water aggregates (oligomers) present in FZ; while its antifungal activity is retained [19, 40, 41]. This formulation is inexpensive and can be used to improve the therapeutic index of AmB against candidiasis and cryptococcosis and to encourage the more widespread use of AmB [40].

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arrangement of AmB monomers with negative chirality (left hand screw sense) would give rise to a bilobed CD spectrum with a short wavelength (high energy) band of positive sign [52]. Thus the spectra of H-AmB suggest a retention of the negative “chirality”' of AmB monomer assembly but point to a change in geometry and/or distance between monomers. THERMODYNAMIC STABILITY OF THE AmB INCREASES ON POLY-AGGREGATION The new super-aggregated form of AmB, which results from condensation of the aggregated form with the monomers appears to be in equilibrium with the monomeric form, independently of the other aggregated form [19, 31]. Relative proportions of the two aggregation states (soluble oligomeric aggregates and insoluble super-aggregates) and of the monomer at various concentrations can be calculated from their characteristic spectroscopic properties. Physico-chemical studies have shown that the rate constants and amplitudes of dissociation of AmB from aggregates or superaggregates to monomers are greater for unheated FZ than for HAmB. The dilution of both the heated and the unheated AmB solution from 10-5 M to 10-7 M at room temperature leads to a progressive dissociation of the aggregates into the monomeric form. Gaboriau and co-workers [19] have shown that the monomer/ aggregate equilibrium is shifted slightly toward its aggregate for HAmB compared with FZ. The concentration where the aggregate is half-dissociated (50% of aggregates and monomeric form) is ~1.0 M for FZ and ~0.5 M for H-AmB in buffer. The higher thermodynamic stability of the superaggregated form influences its association with membranes or lipidic carriers such as lipoproteins. A small amount of decrease (5-10%) of these super-aggregated species occurs after 1 h incubation at 37°C under stirring. Under same incubation conditions, the lower chemical stability of the other aggregated (soluble oligomeric) state pemits a 40 to 50% decrease in the amount of this species [19]. This loss of AmB is an oxygen-dependent process which does not occur in deaerated FZ

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sion originates from the S1 level (Fig. 2), while in the case of the aggregated structures, fluorescence originates from the excitonic band, located below the S1 level on the energy scale [51]. Fluorescence excitation and emission spectra for FZ and H-AmB show expected S1 S0 fluorescence emission as well as anti-Kasha fluorescence emission from the S2 state [44]. The excitation and S1  S0 emission spectra of H-AmB were similar to those of FZ, while the S2  S0 fluorescence differs in intensity between them. Moreover, both FZ and H-AmB exhibited a similar stability to disaggregation by added sodium dodecyl sulfate (SDS) surfactant [44]. Measuring optical activity of the AmB aggregates by CD spectroscopy, represents one of the most sensitive methods for monitoring subtle changes in the supramolecular structure of strongly absorbing molecules [52]. The chromophore of the monomer of AmB is rather symmetric and so has very weak optical activity compared with the oligomer. There is a change in the CD intensity on heating of FZ, with a blue shift in the CD crossover point from 332 to 318 nm. This shift corresponds to the shift in absorption maximum and agrees well with previous spectroscopic data [19]. It should be noted that both absorption spectroscopy in methanol and reversed-phase HPLC indicates that no chemical change in AmB occurs during this treatment; hence, all the changes in structure and activity can be attributed to supramolecular structure change [53]. It is however, noteworthy that bath sonication for >30 min causes no change in the CD spectra of H-AmB, suggesting that the spectral changes are associated with a new, local, supramolecular species rather than merely large undifferentiated aggregates. This supra-molecular structure possesses significant “permanence” because lyophilized preparations retain much of the spectral blue shift and characteristic CD on reconstitution. The bilobed CD band arises from excitonic coupling of the transition moments of a regular (or at least dominant) array of AmB molecules [26, 31, 54, 55]. According to exciton chirality theory, an arrangement of AmB monomers showing positive chirality (right hand screw sense) would give rise to a bilobed CD spectrum with a short wavelength (high energy) band of negative sign, whereas the

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Fig. (2). Schematic diagram of AmB electronic energy levels. 11Ag, 21Ag , and 11Bu states are alternately denoted as S0, S1 and S2. Energy levels for higher order aggregates of AmB depend deeply on nature and size of aggregate. Note the peculiar splitting of the excited-state energy level upon aggregation. This splitting between the exciton bands broadens with an increase in the aggregation level, doubling in separation from dimer to infinite aggregate; and is responsible for light absorption at 336 nm and 326 nm, observed in the short wavelength region of the absorption spectra of super-aggregated structures.

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TOXIC EFFECTS OF AmB ARE DIMINISHED UPON SUPER-AGGREGATION At low concentrations (7 mg/kg) [39]. However, liver toxicity was observed at much lower dosages (>3 mg/kg). Apparently, if treated with H-AmB or Hc-AmB, mice are protected from the acute toxic effects seen with conventional FZ. The observed liver toxicity might be the result of increased AmB concentrations in the liver after administration of H-AmB or HcAmB. It is also conceivable that during circulation in the blood, AmB is transferred from H-AmB to lipoproteins [12, 13], by which specific transport of AmB to hepatocytes might occur. The reduced level of H-AmB toxicity may be explained by the presence of a super-aggregated form of AmB following heat treatment. It has been hypothesized that the super-aggregated form of AmB does not form channels in the membrane, unlike the aggregated form, but exists near the membrane, releasing monomers of AmB which selectively permeate ergosterol-containing membranes (namely, fungal membranes) [2, 3].

SUPRA-MOLECULAR FORM OF AmB ATTENUATES ITS ABILITY TO INDUCE POTENTIALLY HARMFUL CYTOKINES AmB has been shown to induce the production of Interleukin (IL)-1 and tumour necrosis factor (TNF-) in human and murine monocytes [77-80]. Infusion-related fever, and rigors associated with AmB administration are believed to be a result of the production of these cytokines [79, 80]. FZ and AmBisome have been compared directly in vivo in humans and it was shown that less TNF- and IL-1 was found in the plasma of the patients receiving AmBisome [81]. Other cytokines and chemokines that have been shown to be induced by AmB include IL-1 receptor

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encapsulated in human albumin microspheres), with both P-AmB and MP-AmB showing similar levels of plasma AmB [62-64]. However, in kidneys, the highest AmB concentrations were produced by FZ, suggesting a potentially higher nephrotoxicity; with H-AmB showing lower kidney AmB concentrations in rabbits [62]. Espada and co-workers demonstrated that P-AmB as well as MP-AmB yielded lower AmB concentrations in mouse kidneys and plasma as compared with FZ [63, 64]. AmB concentrations in the kidneys from animals treated with P-AmB were significantly higher than the ones obtained with MP-AmB; suggesting microencapsulation significantly decreased kidney uptake in mice [63, 64]. The bulk of AmB was found in the liver, where the pattern was different from that seen in kidneys [63, 64]. In this organ, AmB levels were higher in the animals receiving formulations P-AmB and MP-AmB than in those receiving FZ; with similar AmB concentration for both poly-aggregated formulations. High hepatic AmB concentrations were found even 7 days post-treatment with PAmB and MP-AmB, which suggests a high affinity for this organ [63, 64]. In the spleen, AmB concentrations showed a similar pattern to that observed in the liver, although the clearing was faster, since AmB could be detected for up to 4 days in the spleen from animals treated with H-AmB and MP-AmB [63, 64]. Lung and spleen AmB concentrations, although not significantly different, were greater in rabbits administered with FZ than in those administered with H-AmB. No significant differences in heart AmB concentrations between rabbits administered with either FZ or HAmB were observed [62]. The relative tissue AmB concentrations depending on the formulation reflect the effect of the formulation on the AmB distribution in the body. The values lower than 1 in plasma and kidneys obtained with both P-AmB/FZ and MP-AmB/FZ ratios indicate that AmB in a poly-aggregated form renders lower concentrations than the less aggregated FZ formulation [63, 64]. This effect is even increased by the microencapsulation of polyaggregated AmB (MP-AmB) [63, 64]. The effect of microencapsulation is significant in the kidneys, where lower values were obtained for MP-AmB/FZ than for P-AmB/FZ. At the same time, values higher than 1 in liver and spleen indicate that polyaggregated formulations, specially the microencapsulated one, are targeted to the spleen and the liver, where the high AmB concentrations are maintained for several days [63, 64]. In another study, effect of alternative dosing schedules of polyaggregated AmB on the AmB concentrations in plasma and different organs were assayed in murine model of disseminated candidiasis [63, 64]. The low acute toxicity of P-AmB formulation reported previously [35, 36, 63, 64], allowed the authors to administer high doses of this preparation. Candida-infected mice were treated with six doses (once-weekly) with either FZ (1 mg/kg) or P-AmB (5 mg/kg) and AmB concentrations was measured on day 45 post infection. They demonstrated that P-AmB yielded high concentrations of AmB in the liver and spleen (10-fold higher levels in spleen), whereas levels in plasma and kidneys were relatively lower as compared with the reference formulation FZ [63, 64]. Taken together, these findings suggest that the heat treatment of FZ to change it into a super-aggregated complex would increase its clearance from the systemic circulation resulting in a greater distribution into the liver and possibly less AmB concentration in the kidney. This decrease in kidney distribution may be one reason for diminished AmB-induced renal toxicity of H-AmB. Hartsel and others have shown that heat treatment of FZ results in a condensation of monomeric and aggregated forms of AmB [20, 53, 67]. This condensation results in a larger, physiologically stable super-aggregated complex, which appears to be more susceptible to circulating macrophages, which in turn would deliver more drug to tissues rich in phagocytes such as the liver. Moreover, this advocates the notion that the reticulo-endothelial system constitutes

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HIGHER ACCUMULATION OF SUPER-AGGREGATED AmB OCCURS IN RETICULO-ENDOTHELIAL ORGANS The aggregation state of AmB affects its distribution in the body after intravenous administration. The aggregated forms of AmB can be cleared by the reticulo-endothelial system, as has been previously studied in macrophage cultured cell lines [65]. If the same occurs in vivo, a different body distribution should be obtained in comparison with non-aggregated forms of AmB. Only a limited number of reports are available regarding bio-distribution of super-aggregated form of AmB. The tissue distribution of H-AmB studied by Kwong et al. is one of them [62]. These authors reported differences in AmB disposition, tissue distribution, and AmBinduced renal toxicity following the administration of H-AmB to rabbits compared to values for rabbits administered with FZ. They found that the aggregation of AmB induced by the heat treatment significantly decreases plasma concentrations and increases liver concentration with respect to conventional AmB. The AmB AUC after administration of a single i.v. dose of H-AmB in rabbits was significantly lower than the AUC in FZ administered rabbits [62]. This result could be explained by the fact that the systemic clearance of AmB was significantly higher in rabbits administered with H-AmB than in rabbits administered with FZ. Furthermore, the volume of distribution (Vd) of AmB following H-AmB administration was not significantly different from that following FZ administration, suggesting that binding differences probably don’t account for changes in disposition. Kidneys are the principal organs affected by AmB toxicity and are one of the organs where the evolution of the systemic candidiasis is being studied [84, 85]. FZ rendered higher plasma AmB concentrations than formulation P-AmB/H-AmB (free polyaggregated AmB) or MP-AmB (poly-aggregates micro-

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antagonist (Ra), IL-8, macrophage inflammatory protein (MIP)-1, MIP-1 and monocyte chemo-attractant protein (MCP)-1 [78]. These molecules may contribute to AmB associated toxicity. Additionally, they may also support favourably to the antifungal activity of AmB through their immunomodulatory actions. It was shown that heated as well as unheated preparations induced TNF- secretion at 5 M, but the H-AmB induced only ~30% of the levels induced by FZ. Little response for either was observed at 0.1 m) structures are cleared from the blood by the mononuclear phagocyte system [90]. The large size of the aggregates (600 nm) perhaps allows them to be efficiently captured by the mononuclear phagocyte system and to be transferred to the site of infection with amastigotes. This formulation could also act as a reservoir for monomeric AmB. H-AmB exhibit a greater in vitro anti-plasmodicidal effect than AmB against both chloroquine-resistant (strain K-1) and chloroquine-susceptible (strain FCR-3) Plasmodium falciparum strains [91]. The 50% inhibitory concentrations of H-AmB were similar for both K-1 and FCR-3 strains [91]. The authors showed that in the presence of 1.0 g of H-AmB per ml, only pyknotic parasites were observed after 24 h of incubation of early trophozoites (ring forms). However, when late trophozoites and schizonts were cultured with H-AmB, those forms multiplied to ring forms but the number of infected erythrocytes did not increase [91]. The growth curves of asynchronous parasites showed that AmB has a greater inhibitory effect than H-AmB, but significant differences were observed only at high concentrations that would not be applicable to treatment for malaria [91]. When H-AmB was added to synchronized mature-stage (late trophozoite and schizont) cultures, ring-form parasites that had multiplied successfully invaded and remained inside the RBCs for 12 to 24 h of incubation, indicating that H-AmB has a greater hemolytic effect against parasitized RBC (pRBCs) than it does against non-pRBCs [91]. It has been reported that increased amounts of reactive oxygen species are generated during malaria infection, leading to RBC membrane damage [92, 93]. This may explain the higher levels of plasmodicidal activity and hemolytic activity of H-AmB against pRBCs, the greater effect of H-AmB against ring forms than against late trophozoites and schizonts, and the apparently different antimalarial mechanism of H-AmB compared with those of quinoline antimalarial drugs. The effect of thermal treatment of AmB solutions on the growth kinetics of Candida albicans is much weaker than its effect on RBC membranes. Assuming that the stability of the heat-treated samples (mainly super-aggregated forms) reflects their low efficiency at

producing reactive oxygen species, it suggests that the AmBinduced peroxidative process in fungal cells is less relevant than that in RBCs. The antifungal effects of short- and long-term exposures to the antibiotic were compared to evaluate the influence of autoxidation property on its activity [19]. In experiments assessing the antifungal effects of short-term exposures to AmB, the fungal cells were preincubated for 20 min with various AmB formulations. The time required to reach half of the cell density with respect to that at confluency (t50) was calculated. For concentrations lower than 1 M, thermal pre-treatment of the FZ solutions does not significantly modify the effect of antibiotic on the growth kinetics. A 20% decrease in the t50 values with respect to those for the unheated samples for higher concentrations (5 M), suggested a slightly reduced antifungal effect. Based on the relationship between cell seeding density (CSD) and values of t50, surviving fraction of C. albicans cells able to divide after the antibiotic treatment was estimated [19]. The values of t50 were slightly lower for the cells treated with 1 and 5 M heated AmB colloidal solutions, corresponding to CSD decreases of 34 and 45%, respectively. Assuming the presence of the same percentage of each spectroscopic species from 1 and 5 mM FZ solutions (before and after heating at 70°C) with or without cells, comparison of these concentrations and their respective effects on the growth kinetics indicated a slightly higher efficiency of the soluble aggregates on C. albicans cells with respect to that of the super-aggregated species [19]. These results suggested that heated colloidal solutions were only slightly less efficient than the unheated ones at inhibiting the growth of C. albicans cells in vitro. In the experiments assessing the antifungal effects of long-term exposures to AmB, the antibiotic was kept in the incubation medium for 15 h during cell growth. For long-term exposures, the heat treatment does not change the fungistatic and fungicidal activities of AmB solutions. The efficiency of its antifungal activity seems consistent with data obtained by Rogers et al; which found no appreciable difference in MIC (minimum inhibitory concentration) and IC50 (50% inhibitory concentration) for both FZ and H-AmB against several Candida species [83]. Moreover, the in vitro activity against Candida parapisilosis (Cp) suggests that both FZ and H-AmB were very effective; with H-AmB being slightly more active than FZ over the whole range of concentration [42]. A comparative study of efficacy with three AmB formulations, FZ, free or microencapsulated poly-aggregates (FZ, P-AmB and MP-AmB) was performed in a murine model of systemic C. albicans infection [63, 64]. They established 72 h as the time between infection and treatment of mice keeping the fact in mind that diagnosis of systemic candidiasis is rarely reached in the early stages of infection; thereby diagnosed only at autopsy [94]. No significant differences in the efficacy were found in relation to the conventional treatment (FZ). Moreover, they also showed that the decrease in AmB concentration in kidneys did not reduce efficacy in clearing the fungal load in this organ, although the nephrotoxicity was appreciably reduced [63, 64]. Lower toxicity permits an increase in the therapeutic index as compared with the AmB conventional formulation, and makes them suitable for the treatment of candidiasis. Petit and co-workers studied the efficacy of single injections of heated and unheated FZ by assessing the mice survival in experimental murine candidiasis model [40]. Immediate toxicity following injection of FZ solutions in infected mice limited its antifungal efficiency. In murine model of candidiasis, treatment with a single dose of H-AmB (0.5 mg/kg), maintained a survival rate of 85% for 3 weeks, whereas at the same dose the immediate toxicity of the standard formulation (FZ) in infected mice restricted its therapeutic efficacy to 25% survival [40].

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a major pathway for the accumulation of poly-aggregated forms of AmB. Furthermore, the observations that the liver AmB concentration is increased and the AmB AUC is decreased with no significant differences in Vss (volume of distribution at steady state) following H-AmB administration further support the hypothesis that the super-aggregated form of AmB has a higher disposition for the liver while sparing other tissues [62]. Similar behaviour is previously reported for other microparticulate delivery systems like liposomes, nanospheres or lipid complex [86-89].

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AmB and unheated FZ (2.4 mg/kg), were equally effective. When treatment was given later (30 h after infection), it was found to be ineffective [40]. MTD of each formulation was found to vary with the model of infection, the severity of the infection at the time of treatment, and the strain of mouse. In case of cryptococcal pneumonia, the MTD of unheated FZ was 2.4 mg/kg, while the MTD of heated H-AmB was not determined. For cryptococcal meningoencephalitis, the heated H-AmB solutions were at least four times less toxic than unheated ones, enabling authors to inject higher doses of AmB safely [40]. Heated H-AmB given at the dose 2.4 and 4.8 mg/kg was more efficient than the MTD of unheated FZ (1.2 mg/kg), 48 h after infection. Therefore, the antifungal activity was enhanced, increasing the mean survival times of the mice by a factor of 1.4 [40]. It has been suggested that extracellular phospholipases produced by certain fungal strains may cause the disruption of HAmB into the active monomeric form, and as a consequence, these strains are just as susceptible to H-AmB as they are to FZ [62]. Swenson et al. have previously demonstrated that extracellular lipases produced by certain strains of C. albicans are able to hydrolyze the major lipid in ABLC, releasing active AmB. They also showed that the C. albicans mutant strains resistant to ABLC were in fact deficient in extracellular phospholipase production [104]. The addition of exogenous phospholipase to the incubation medium of these strains restored their sensitivity to ABLC. However, studies to confirm that a similar phenomenon happens with H-AmB are warranted.

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CONCLUSION The idea that a micellar complex could change its physicochemical property by simple heating remained completely undiscovered since the first works of Ernst et al. [105]. Almost twenty years later, Gaboriau et al. produced a major study about this phenomenon by discovering the super-aggregated form of AmB [19]. This new AmB species not only presents an important change in the absorption and CD spectra of AmB, which is related to its physicochemical state, but also reveals a biological difference when compared to the unheated micelle [19, 41, 67, 83]. Unlike the AmB soluble aggregate species, the dissociation of this super-aggregated form into monomers occurs at lower AmB concentrations [53]. Therefore, it can be inferred that the AmB super-aggregated species may act as a reservoir of AmB monomers that releases only a limited amount of monomeric AmB species in the aqueous media. As a consequence, the concentration of monomer might be below its critical aggregation concentration (~106 M); thus, the drug can remain in its monomeric form. This form would be able to bind to the ergosterol of fungal cells, but unable to bind to the mammalian cholesterol [22]. It is well-established that the monomeric species of AmB is less effective than the soluble aggregated form in inducing permeability of membranes containing cholesterol, leading to potassium leakage [32]. On the other hand, the soluble soluble aggregated form present in FZ was shown to trigger permeability changes in RBC membranes and to induce cytotoxic events [22]. Such correlation was also maintained in several in vivo studies [29, 104]. The probable mechanism behind this pattern of activity could be attributed - in part - to the high chemical stability of the AmB super-aggregates, which are less susceptible to peroxidative process than the aggregated form and, therefore, present less affinity to membranes containing cholesterol than the unheated preparation [67]. Also, this protection against the peroxidation process allows the AmB super-aggregated form to control the release of the monomeric AmB species, which is able to maintain its antifungal activity [22]. Therefore, a complete resculpting of AmB aggregates probably occurs with the mild heating process, and this phenomenon induces changes in the AmB distribution and interaction with various serum fractions [53].

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Therapeutic efficacy of FZ and its derivatives was determined in a model of severe invasive candidiasis in persistently leukopenic mice; evaluating the effect of early or delayed treatment on the survival of leukopenic mice and growth of C. albicans in the kidney. By increasing the delay between C. albicans inoculation and the time of treatment, the efficacy of treatment in relation to the severity of infection was also investigated. FZ administered i.v. as a single dose of MTD (0.8 mg/kg), 6 h after C. albicans inoculation was only partially effective. Similar results were obtained after treatment with either H-AmB or Hc-AmB (centrifuged H-AmB resuspended in 5% dextrose) at 0.8 mg/kg. However, both H-AmB and Hc-AmB were more effective than FZ at a higher dose (3 mg/kg) showing 100% survival and significant reduction of the numbers of viable C. albicans in the kidney 7 days after inoculation [39]. When treatment was delayed to 16 h after inoculation, it was clearly demonstrated that for both H-AmB and Hc-AmB, a six-fold higher dose (0.6 mg/kg) were appreciably tolerated than those for FZ (0.1 mg/kg), resulting in significantly improved therapeutic efficacy. Furthermore, it became evident that the H-AmB formulation is not further improved by centrifugation [39]. Although recommend guidelines for the treatment of candidiasis is a therapy with AmB consisting of daily dosing [95, 96], some non-clinical studies have shown that these formulations can be given every other day to reduce fungal burden [97, 98]. Moreover, a study was carried out in a murine model of disseminated candidiasis with two different intermittent dose regimens. The doses were based on preliminary studies related to the toxicity of different formulations of AmB [35, 36, 63, 64]. In the first study, groups of mice were given a high initial dose of PAmB (free poly-aggregated AmB) or microencapsulated form (MPAmB) at 10 mg/kg bw on day 3 and a subsequent dose of 3 mg/kg bw on day 24 after infection with C. albicans. In the subsequent study, once weekly dosing schedule of 5 mg/kg (of P-AmB) was chosen to determine therapeutic efficacy of alternative dosing regimens [63, 64]. In both studies, FZ was administered as two doses of 1 mg/kg bw because its 50% lethal dose (LD50) is ca. 2–3 mg/kg [99-101]. With respect to the first multiple dose regime, all three formulations proved to be significantly more efficient compared with the untreated group. The study suggested that microencapsulation of AmB super-aggregates does not improve treatment efficacy with respect to free poly-aggregates [63, 64]. The results of the second efficacy experiment, involving AmB formulations being given intermittently once a week for 6 weeks, showed similar efficacy for both preparations (P-AmB and FZ) in the prolongation of animal survival compared with the untreated control group. Additionally, no significant differences were found between the two treatment regimens [63, 64]. Nevertheless, higher doses of polyaggregated AmB formulation administered in the study obtained the same antifungal effect achieved with the FZ formulation on an mg/kg basis [63, 64]. These results coincide with those reported previously in other animal model with different lipid preparations [97, 98, 102, 103]. To date, few reports evaluating the effectiveness of H-AmB versus that of FZ against Cryptococcus clinical isolates have been carried out. Studies demonstrated that H-AmB is more toxic than or as toxic as FZ to a variety of cryptococcus fungal strains [38]. For both FZ and H-AmB, the concentration range which resulted in a 50% reduction of the growth of fungal cells was 0.125-1.0 mg/ml. All of the cultures tested shared the same range of values for 50% reduction in growth regardless of the source of the isolate (human, animal, or environmental) [38]. In-vivo advantage of H-AmB over unheated FZ has been tested in murine model of cryptococcosis [40]. For acute cryptococcal pneumonia, mice were treated 24 h after infection (before they were severely ill). Both forms of AmB significantly increased the survival of mice compared with the control. Identical doses of H-

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Fig. (3). Model of AmB uptake and cytotoxicity of various aggregated and monomeric forms. Heating for 20 min at 70°C leads to the super-aggregation of AmB. The dissociation of the super-aggregates (H-AmB) into the monomeric form occurs at concentrations lower than those for the soluble aggregates (FZ). This higher thermodynamic stability enables H-AmB to maintain their entity for longer duration, releasing monomers at a sustained rate. The monomers can then act on fungal cells while sparing mammalian membranes. On the other side, the soluble aggregates of FZ attacks cholesterol of mammalian cells causing severe toxic reactions. Moreover, the large size of super-aggregates (higher number of AmB molecules in the ‘super-aggregates’) results in efficient endocytosis and higher AmB uptake into macrophage reservoirs. These monocyte/macrophages then deliver bulk of their payload to reticulo-endothelial organs (liver and spleen), with kidneys showing lower AmB bio-distribution. In contrast, higher accumulation of FZ aggregates occur in kidneys, causing nephrotoxicity. Thus, H-AmB exhibits much lower cytotoxicity than FZ in various cell lines as well as in mice, without compromising its antifungal activity.

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Another mechanistic rationale for the similar efficacy and lower toxicity of H-AmB as compared to FZ, could be that FZ can be rapidly converted from its aggregated form to a protein bound monomer in the presence of human serum albumin, whereas HAmB demonstrates greater stability by persisting as a stable inactive aggregate [67]. This little loss of integrity in serum as well as large size permits higher uptake by circulating macrophages, which deliver much of their payload to reticulo-endothelial organs sparing kidney and other tissues; ultimately resulting in lower toxic side effects (Fig. 3). Lower cytotoxicity permits higher dosing regimens, increasing the therapeutic index as compared with the conventional formulation, and makes them suitable for the treatment of an array of fungal diseases. Moreover, in infections in which the AmB susceptible pathogen is preferentially located in liver or spleen, the new poly-aggregated AmB formulations have proved to be especially effective, as in the case of visceral leishmaniasis, where Leishmania amastigotes are located in the mononuclear phagocyte cells of the reticulo-endothelial system. In this case, the aggregation of AmB molecules, either by heat [41] or by pH-dependent procedure [35, 36], clearly improves its activity with respect to conventional AmB. In the same way, Bau et al. showed the benefits of the patent-free heated AmB product for use by public-health

authorities or a reactive non-governmental organization for treatment of leishmaniasis and other neglected diseases [106]. Therefore, it can be concluded that AmB super-aggregated form has taken one step closer towards providing a solution to growing demand of an active, less toxic substitute of AmB. CONFLICT OF INTEREST The authors confirm that this article content has no conflict of interest. ACKNOWLEDGEMENTS Qamar Zia and Asim Azhar are thankful to Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India. Ghulam Md Ashraf is grateful to King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia for the facilities. REFERENCES [1]

Bodey GP. Infection in cancer patients: A continuing association. Am J Med 1986; 81(1A): 11-26.

Current Pharmaceutical Design, 2016, Vol. 22, No. 7

Super Aggregated form of Amphotericin B

[7] [8] [9]

[10] [11] [12]

[31]

[32]

[33]

[34] [35]

[36]

[19]

[20] [21]

[22]

[23]

[24] [25]

[26]

tri

is

rd

[38]

[39]

fo

ot

[18]

[37]

[40]

N

[17]

rs

[16]

Pe

[15]

on

al

[14]

us

e

[13]

[30]

n

[6]

[29]

tio

[5]

[28]

ly

[4]

[27]

amphotericin B: lipid state and cholesterol content dependence. Biochim Biophys Acta 1980; 599(1): 280-93. Hemenger RP, Kaplan T, Gray LJ. Structure of amphotericin B aggregates based on calculations of optical spectra. Biopolymers 1983; 22(3): 911-8. Lamy-Freund MT, Schreier S, Peitzsch RM, Reed WF. Characterization and time dependence of amphotericin B: deoxycholate aggregation by quasielastic light scattering. J Pharm Sci 1991; 80(3): 262-6. Barwicz J, Christian S, Gruda I. Effects of the aggregation state of amphotericin B on its toxicity to mice. Antimicrob Agents Chemother 1992; 36(10): 2310-5. Bennett JE, Hill GJ, Butler WT, Emmons CW. Correlation of particle size of intravenous amphotericin B with toxic and chemotherapeutic effects. Antimicrob Agents Chemother 1963; 161: 745-52. Bolard J, Legrand P, Heitz F, Cybulska B. One-sided action of amphotericin B on cholesterol-containing membranes is determined by its self-association in the medium. Biochem 1991; 30(23): 570715. Hartsel SC, Benz SK, Ayenew W, Bolard J. Na+, K+ and Clselectivity of the permeability pathways induced through sterolcontaining membrane vesicles by amphotericin B and other polyene antibiotics. Eur Biophys J 1994; 23(2): 125-32. Adams ML, Andes DR, Kwon GS. Amphotericin B encapsulated in micelles based on poly(ethylene oxide)-block-poly(L-amino acid) derivatives exerts reduced in vitro hemolysis but maintains potent in vivo antifungal activity. Biomacromol 2003; 4(3): 750-7. Vakil R, Kwon GS. PEG-phospholipid micelles for the delivery of amphotericin B. J Control Release 2005; 101(1-3): 386-9. Sánchez-Brunete JA, Dea MA, Rama S, et al. Treatment of experimental visceral leishmaniasis with amphotericin B in stable albumin microspheres. Antimicrob Agents Chemother 2004; 48(9): 3246-52. Sánchez-Brunete JA, Dea MA, Rama S, et al. Amphotericin B molecular organization as an essential factor to improve activity/toxicity ratio in the treatment of visceral leishmaniasis. J Drug Target 2004; 12(7): 453-60. Burgess BL, He Y, Baker MM, et al. NanoDisk containing super aggregated amphotericin B: a high therapeutic index antifungal formulation with enhanced potency. Int J Nanomed 2013; 8: 473343. Bartlett K, Yau E, Hartsel SC, et al. Effect of heat-treated amphotericin B on renal and fungal cytotoxicity. Antimicrob Agents Chemother 2004; 48(1): 333-6. van Etten EW, van Vianen W, Roovers P, Frederik P. Mild heating of amphotericin B-desoxycholate: effects on ultrastructure, in vitro activity and toxicity, and therapeutic efficacy in severe candidiasis in leukopenic mice. Antimicrob Agents Chemother 2000; 44(6): 1598-603. Petit C, Chéron M, Joly V, Rodrigues JM, Bolard J, Gaboriau F. Invivo therapeutic efficacy in experimental murine mycoses of a new formulation of deoxycholate-amphotericin B obtained by mild heating. J Antimicrob Chemother 1998; 42(6): 779-85. Petit C, Yardley V, Gaboriau F, Bolard J, Croft SL. Activity of a heat-induced reformulation of amphotericin B deoxycholate (Fungizone) against Leishmania donovani. Antimicrob Agents Chemother 1999; 43(2): 390-2. da Silva-Filho MA, da Silva Siqueira SDV, et al. How can micelle systems be rebuilt by a heating process? Int J Nanomed 2012; 7: 141-50. Gruszecki WI, Gago M, Here M. Dimers of polyene antibiotic amphotericin B detected by means of fluorescence spectroscopy: molecular organization in solution and in lipid membranes. J Photochem Photobiol B Biol 2003; 69(1): 49-57. Stoodley R, Wasan KM, Bizzotto D. Fluorescence of amphotericin B-deoxycholate (Fungizone) monomers and aggregates and the effect of heat-treatment. Langmuir 2007; 23(17): 8718-25. Kasha M. Energy transfer mechanisms and the molecular exciton model for molecular aggregates. Radiation Res 1963; 20(1): 55-70. Gruszecki WI, Luchowski R, Gago M, et al. Molecular organization of antifungal antibiotic amphotericin B in lipid monolayers studied by means of fluorescence lifetime Imaging microscopy. Biophys Chem 2009; 143(1-2): 95-101.

bu

[3]

Chabot GG, Pazdur R, Valeriote FA, Baker LH. Pharmacokinetics and toxicity of continuous infusion amphotericin B in cancer patients. J Pharm Sci 1989; 78(4): 307-10. Chavanet P, Joly V, Rigaud D, Bolard J, Carbon C, Yeni P. Influence of diet on experimental toxicity of amphotericin B deoxycholate. Antimicrob Agents Chemother 1994; 38(5): 963-8. Rothon DA, Mathias RG, Schechter MT. Prevalence of HIV infection in provincial prisons in British Columbia. CMAJ 1994; 151(6): 781-7. Meyer RD. Current role of therapy with amphotericin B. Clin Infect Dis 1992; 14(S1): S154-60. Hartsel S, Bolard J. Amphotericin B: new life for an old drug. Trends Pharmacol Sci 1996; 17(12): 445-9. Chapman SW, Sullivan DC, Cleary JD. In search of the holy grail of antifungal therapy. Trans Am Clin Climatol Assoc 2008; 119: 197-216. Ellis D. Amphotericin B: spectrum and resistance. J Antimicrob Chemother 2002; 49(Suppl 1): 7-10. Bates DW, Su L, Yu DT, et al. Correlates of acute renal failure in patients receiving parenteral amphotericin B. Kidney Int 2001; 60(4): 1452-9. Gates C, Pinney RJ. Amphotericin B and its delivery by liposomal and lipid formulations. J Clin Pharm Ther 1993; 18(3): 147-53. Wasan KM, Conklin JS. Enhanced amphotericin B nephrotoxicity in intensive care patients with elevated levels of low-density lipoprotein cholesterol. Clin Infect Dis 1997; 24(1): 78-80. Wasan KM, Cassidy SM. Role of plasma lipoproteins in modifying the biological activity of hydrophobic drugs. J Pharm Sci 1998; 87(4): 411-24. Wasan KM, Kennedy AL, Cassidy SMR, et al. Pharmacokinetics, distribution in serum lipoproteins and tissues, and renal toxicities of amphotericin B and amphotericin B lipid complex in a hypercholesterolemic rabbit model: single-dose studies. Antimicrob Agents Chemother 1998; 42(12): 3146-52. Wasan KM, Vadiei K, Lopez-Berestein G, Luke DR. Pharmacokinetics, tissue distribution, and toxicity of free and liposomal amphotericin B in diabetic rats. J Infect Dis 1990; 161(3): 562-6. Wasan KM, Rosenblum MG, Cheung L, Lopez-Berestein G. Influence of lipoproteins on renal cytotoxicity and antifungal activity of amphotericin B. Antimicrob Agents Chemother 1994; 38(2): 223-7. Dupont B. Overview of the lipid formulations of amphotericin B. J Antimicrob Chemother 2002; 49(Suppl 1): 31-6. Wong-Beringer A, Jacobs RA, Guglielmo BJ. Lipid formulations of amphotericin B: clinical efficacy and toxicities. Clin Infect Dis 1998; 27(3): 603-18. Brajtburg J, Bolard J. Carrier effects on biological activity of amphotericin B. Clin Microbiol Rev 1996; 9(4): 512-31. Gaboriau F, Chéron M, Petit C, Bolard J. Heat-induced superaggregation of amphotericin B reduces its in vitro toxicity: a new way to improve its therapeutic index. Antimicrob Agents Chemother 1997; 41(11): 2345-51. Lambing HE, Wolf BD, Hartsel SC. Temperature effects on the aggregation state and activity of amphotericin B. Biochim Biophys Acta 1993; 1152(1): 185-8. Lamy-Freund MT, Ferreira VF, Schreier S. Polydispersity of aggregates formed by the polyene antibiotic amphotericin B and deoxycholate. A spin label study. Biochim Biophys Acta 1989; 981(2): 207-12. Legrand P, Romero EA, Cohen BE, Bolard J. Effects of aggregation and solvent on the toxicity of amphotericin B to human erythrocytes. Antimicrob Agents Chemother 1992; 36(11): 251822. Mazerski J, Grzybowska J, Borowski E. Influence of net charge on the aggregation and solubility behaviour of amphotericin B and its derivatives in aqueous media. Eur Biophys J 1990; 18(3): 159-64. Balakrishnan AR, Easwaran KR. CD and NMR studies on the aggregation of amphotericin-B in solution. Biochim Biophys Acta 1993; 1148(2): 269-77. Barwicz J, Gruszecki WI, Gruda I. Spontaneous organization of amphotericin B in aqueous medium. J Colloid Interf Sci 1993; 158(1): 71-6. Bolard J, Seigneuret M, Boudet G. Interaction between phospholipid bilayer membranes and the polyene antibiotic

on

[2]

[41]

[42]

[43]

[44] [45] [46]

801

802 Current Pharmaceutical Design, 2016, Vol. 22, No. 7

[59]

[60] [61]

[63] [64]

[65]

[66]

[67]

[68]

ly

[77] [78]

tio

[76]

n

on

N

[62]

[75]

bu

[58]

[74]

tri

[57]

[73]

density lipoprotein coat lipid content. J Pharm Sci 1999; 88(11): 1149-55. Wasan KM, Brazeau GA, Keyhani A, Hayman AC, LopezBerestein G. Roles of liposome composition and temperature in distribution of amphotericin B in serum lipoproteins. Antimicrob Agents Chemother 1993; 37(2): 246-50. Wasan KM, Lopez-Berestein G. The influence of serum lipoproteins on the pharmaco- kinetics and pharmacodynamics of lipophilic drugs and drug carriers. Arch Med Res 1993; 24(4): 395401. Wasan KM, Morton RE, Rosenblum MG, Lopez-Berestein G. Decreased toxicity of liposomal amphotericin B due to association of amphotericin B with high-density lipoproteins: role of lipid transfer protein. J Pharm Sci 1994; 83(7): 1006-10. Wasan KM, Grossie VB, Lopez-Berestein G. Concentrations in serum and distribution in tissue of free and liposomal amphotericin B in rats during continuous intralipid infusion. Antimicrob Agents Chemother 1994; 38(9): 2224-6. Legrand P, Vertut-Doi A, Bolard J. Comparative internalization and recycling of different amphotericin B formulations by a macrophage-like cell line. J Antimicrob Chemother 1996; 37(3): 519-33. Ridente Y, Aubard, J, Bolard J. Absence in amphotericin B-spiked human plasma of the free monomeric drug, as detected by SERS. FEBS Lett 1999; 446(2-3): 283-6. Bekersky I, Fielding RM, Dressler DE, Lee JW, Buell DN, Walsh TJ. Plasma protein binding of amphotericin B and pharmacokinetics of bound versus unbound amphotericin B after administration of intravenous liposomal amphotericin B (AmBisome) and amphotericin B deoxycholate. Antimicrob Agents Chemother 2002; 46(3): 834-40. Bhamra R, Saad A, Bolcsak LE, Janoff AS, Swenson CE. Behavior of amphotericin B lipid complex in plasma in vitro and in the circulation of rats. Antimicrob Agents Chemother 1997; 41(5): 886-92. Rogers PD, Jenkins JK, Chapman SW, Ndebele K, Chapman BA, Cleary JD. Amphotericin B activation of human genes encoding for cytokines. J Infect Dis 1998; 178(6): 1726-33. Rogers PD, Stiles JK, Chapman SW, Cleary JD. Amphotericin B induces expression of genes encoding chemokines and cell adhesion molecules in the human monocytic cell line THP-1. J Infect Dis 2000; 182(4): 1280-3. Goodwin SD, Cleary JD, Walawander CA, Taylor JW, Grasela TH. Pretreatment regimens for adverse events related to infusion of amphotericin B. Clin Infect Dis 1995; 20(4): 755-61. Chia JKS, Pollack M. Amphotericin B induces tumor necrosis factor production by murine macrophages. J Infect Dis 1989; 159(1): 113-6. Arning M, Kliche KO, Heer-Sonderhoff AH, Wehmeier A. Infusion-related toxicity of three different amphotericin B formulations and its relation to cytokine plasma levels. Mycoses 1995; 38(11-12): 459-65. Clayette P, Martin M, Beringue V, et al. Effects of MS-8209, an Amphotericin B derivative, on tumor necrosis factor alpha synthesis and human immunodeficiency virus replication in macrophages. Antimicrob Agents Chemother 2000; 44(2): 405-7. Rogers PD, Barker KS, Herring V, Jacob M. Heat-induced superaggregation of amphotericin B attenuates its ability to induce cytokine and chemokine production in the human monocytic cell line THP-1. J Antimicrob Chemother 2003; 51(2): 405-8. Papadimitriou JM, Ashman RB. The pathogenesis of acute systemic candidiasis in a susceptible inbred mouse strain. J Pathol 1986; 150(4): 257-65. Ryley JF, McGregor S, Lister SC, Jackson KP. Kidney function in experimental systemic candidosis of mice/Die nierenfunktion bei experimenteller systemischer candidose der maus. Mycoses 1988; 31(4): 203-7. Bekersky I, Boswell GW, Hiles R, Fielding RM, Buell D, Walsh TJ. Safety, toxicokinetics and tissue distribution of long-term intravenous liposomal amphotericin B (AmBisome): a 91-day study in rats. Pharm Res 2000; 17(12): 1494-502. Boswell GW, Bekersky I, Buell D, Hiles R, Walsh TJ. Toxicological profile and pharmacokinetics of a unilamellar liposomal vesicle formulation of amphotericin B in rats. Antimicrob Agents Chemother 1998; 42(2): 263-8.

is

[56]

[72]

e

[55]

[71]

[79]

rd

[54]

[70]

us

[53]

fo

[52]

al

[51]

[69]

[80] [81]

ot

[50]

on

[49]

rs

[48]

Christensen RL. The Electronic States of Carotenoids. In: Frank HA, Young AJ, Britton G, Cogdell RJ, Eds. The Photochemistry of carotenoids. Netherlands: Springer 1999; pp. 137-59. Andersson PO, Bachilo SM, Chen R-L, Gillbro T. Solvent and temperature effects on dual fluorescence in a series of carotenes. Energy gap dependence of the internal conversion rate. J Phys Chem 1995; 99(44): 16199-209. Frank HA, Desamero RZB, Chynwat V, et al. Spectroscopic properties of spheroidene analogs having different extents of electron conjugation. J Phys Chem A 1997; 101(2):149-57. Frank HA, Josue JS, Bautista JA, et al. Spectroscopic and photochemical properties of open-chain carotenoids. J Phys Chem B 2002; 106(8): 2083-92. Wasko P, Luchowski R, Tutaj K, Grudzinski W, Adamkiewicz P, Gruszecki WI. Toward understanding of toxic side effects of a polyene antibiotic amphotericin B: fluorescence spectroscopy reveals widespread formation of the specific supramolecular structures of the drug. Mol Pharm 2012; 9(5): 1511-20. Harada N, Nakanishi K. Circular dichroic spectroscopy: exciton coupling in organic stereochemistry. Mills Valley, CA, USA: University Science Books 1983. Baas B, Kindt K, Scott A, Scott J, Mikulecky P, Hartsel SC. Activity and kinetics of dissociation and transfer of amphotericin B from a novel delivery form. AAPS PharmSci 1999; 1(3): 21-31. Bolard J, Cheron M. Association of the polyene antibiotic amphotericin B with phospholipid vesicles: perturbation by temperature changes. Can J Biochem 1982; 60(8): 782-9. Jullien S, Vertut-Croquin A, Brajtburg J, Bolard J. Circular dichroism for the determination of amphotericin B binding to liposomes. Anal Biochem 1988; 172(1): 197-202. Lamy-Freund MT, Ferreira VF, Faljoni-Alário A, Schreier S. Effect of aggregation on the kinetics of autoxidation of the polyene antibiotic amphotericin B. J Pharm Sci 1993; 82(2): 162-6. Brajtburg J, Elberg S, Schwartz DR, et al. Involvement of oxidative damage in erythrocyte lysis induced by amphotericin B. Antimicrob Agents Chemother 1985; 27(2): 172-6. Brajtburg J, Elberg S, Bolard J, et al. Interaction of plasma proteins and lipoproteins with amphotericin B. J Infect Dis 1984; 149(6): 986-97. Fisher PB, Bryson V, Schaffner CP. Polyene macrolide antibiotic cytotoxicity and membrane permeability alterations. II. Phenotypic expression in intraspecific and interspecific somatic cell hybrids. J Cell Physiol 1979; 100(2): 335-42. Sabra R, Branch RA. Effect of amphotericin B on intracellular calcium levels in cultured glomerular mesangial cells. Eur J Pharmacol 1992; 226(1): 79-85. Jewell SA, Bellomo G, Thor H, Orrenius S, Smith M. Bleb formation in hepatocytes during drug metabolism is caused by disturbances in thiol and calcium ion homeostasis. Science 1982; 217(4566): 1257-9. Kwong EH, Ramaswamy M, Bauer EA, Hartsel SC, Wasan KM. Heat treatment of amphotericin B modifies its serum pharmacokinetics, tissue distribution, and renal toxicity following administration of a single intravenous dose to rabbits. Antimicrob Agents Chemother 2001; 45(7): 2060-3. Espada R, Valdespina S, Dea MA, et al. In vivo distribution and therapeutic efficacy of a novel amphotericin B poly-aggregated formulation. J Antimicrob Chemother 2008; 61(5): 1125-31. Espada R, Valdespina S, Molero G, Dea MA, Ballesteros MP, Torrado JJ. Efficacy of alternative dosing regimens of polyaggregated amphotericin B. Int J Antimicrob Agents 2008; 32(1): 55-61. Chéron M, Petit C, Bolard J, Gaboriau F. Heat-induced reformulation of amphotericin B-deoxycholate favours drug uptake by the macrophage-like cell line J774. J Antimicrob Chemother 2003; 52(6): 904-10. Krause HJ, Juliano RL. Interactions of liposome-incorporated amphotericin B with kidney epithelial cell cultures. Mol Pharmacol 1988; 34(3): 286-97. Hartsel SC, Baas B, Bauer E, et al. Heat-induced superaggregation of amphotericin B modifies its interaction with serum proteins and lipoproteins and stimulation of TNF-alpha. J Pharm Sci 2001; 90(2): 124-33. Kennedy AL, Wasan KM. Preferential distribution of amphotericin B lipid complex into human HDL3 is a consequence of high

Pe

[47]

Zia et al.

[82]

[83]

[84]

[85]

[86]

[87]

Super Aggregated form of Amphotericin B

[92]

[93] [94]

[95] [96]

[101]

[102] [103]

[104]

[105]

[106]

bu

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Received: October 26, 2015

tio

us

[97]

[100]

n

[91]

[99]

ly

[90]

[98]

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against coccidioidal meningitis in rabbits. Antimicrob Agents Chemother 2002; 46(8): 2420-6. Adler-Moore JP, Olson JA, Proffitt RT. Alternative dosing regimens of liposomal amphotericin B (AmBisome) effective in treating murine systemic candidiasis. J Antimicrob Chemother 2004; 54: 1096-102. Gondal JA, Swartz RP, Rahman A. Therapeutic evaluation of free and liposome-encapsulated amphotericin B in the treatment of systemic candidiasis in mice. Antimicrob Agents Chemother 1989; 33(9): 1544-8. Clark JM, Whitney RR, Olsen SJ, et al. Amphotericin B lipid complex therapy of experimental fungal infections in mice. Antimicrob Agents Chemother 1991; 35: 615-21. Clemons KV, Stevens DA. Comparative efficacy of amphotericin B colloidal dispersion and amphotericin B deoxycholate suspension in treatment of murine coccidioidomycosis. Antimicrob Agents Chemother 1991; 35: 1829-33. Clemons KV, Stevens DA. Comparison of fungizone, Amphotec, AmBisome, and Abelcet for treatment of systemic murine cryptococcosis. Antimicrob Agents Chemother 1998; 42: 899-902. Clemons KV, Stevens DA. Comparative efficacies of four amphotericin B formulations--Fungizone, amphotec (Amphocil), AmBisome, and Abelcet--against systemic murine aspergillosis. Antimicrob Agents Chemother 2004; 48: 1047-50. Swenson CE, Perkins WR, Roberts P, et al. In vitro and in vivo antifungal activity of amphotericin B lipid complex: Are phospholipases important? Antimicrob Agents Chemother 1998; 42: 767-71. Ernst C, Grange J, Rinnert H, Dupont G, Lematre J. Structure of amphotericin B aggregates as revealed by UV and CD spectroscopies. Biopolymers 1981; 20: 1575-88. Bau P, Bolard J, Dupouy-Camet J. Heated amphotericin to treat leishmaniasis. Lancet Infect Dis 2003; 3: 188.

on

[89]

Echevarría I, Barturen C, Renedo MJ, Trocóniz IF, Dios-Viéitez MC. Comparative pharmacokinetics, tissue distributions, and effects on renal function of novel polymeric formulations of amphotericin B and amphotericin B-deoxycholate in rats. Antimicrob Agents Chemother 2000; 44(4): 898-904. Ostrosky-Zeichner L, Marr KA, Rex JH, Cohen SH. Amphotericin B: time for a new "gold standard". Clin Infect Dis 2003; 37(3): 415-25. Janknegt R, de Marie S, Bakker-Woudenberg IA, Crommelin DJ. Liposomal and lipid formulations of amphotericin B. Clin Pharmacokinet 1992; 23(4): 279-91. Hatabu T, Takada T, Taguchi N, Suzuki M, Sato K, Kano S. Potent plasmodicidal activity of a heat-induced reformulation of deoxycholate-amphotericin B (Fungizone) against Plasmodium falciparum. Antimicrob Agents Chemother 2005; 49(2): 493-6. Greve B, Lehman LG, Lell B, et al. High oxygen radical production is associated with fast parasite clearance in children with Plasmodium falciparum malaria. J Infect Dis 1999; 179(6): 1584-6. Greve B, Kremsner PG, Lell B, Luckner D, Schmid D. Malarial anaemia in African children associated with high oxygen-radical production. Lancet 2000; 355(9197): 40-1. García-Fontgivell JF, Mayayo Artal E. Prevalence of fungal infections detected from biopsies and autopsies in the past 11 years at the University Hospital Joan XXIII in Tarragona, Spain. Rev Iberoam Micol 2006; 23(4): 201-8. Pappas PG, Rex JH, Sobel JD, et al. Guidelines for treatment of candidiasis. Clin Infect Dis 2004; 38(2): 161-89. Rex JH, Walsh TJ, Sobel JD, et al. Practice guidelines for the treatment of candidiasis. Infect Dis Society of America. Clin Infect Dis 2000; 30(4): 662-78. Clemons KV, Sobel RA, Williams PL, Pappagianis D, Stevens DA. Efficacy of intravenous liposomal amphotericin B (AmBisome)

e

[88]

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