药学学报 Acta Pharmaceutica Sinica 2009, 44 (2): 175−180
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Spectrophotometric determination of tranexamic acid using vanillin F.M.A. Rind1*, M.G.H. Laghari1, A.H. Memon1, U.R. Mughal1, F. Almani1, N. Memon1, M.Y. Khuhawar2, M.L. Maheshwari1 (1. Faculty of Pharmacy, University of Sindh, Jamshoro, Pakistan; 2. Institute of Chemistry, Faculty of Natural Sciences, University of Sindh, Jamshoro, Pakistan)
Abstract: A new spectrophotometric method has been examined for the determination of the tranexamic acid (TA) by derivatization with vanillin (VAN). The molar absorptivity of TA was calculated 25 160 L·mol−1·cm−1 at λmax 354 nm and obeyed the Beer’s law within 0.5−2.5 µg·mL−1. The color reaction was highly stable and did not show any change in absorbance up to 24 h. The method was applied for the analysis of TA from capsules, injections and tooth pastes. The amounts of TA found in capsules, injections and tooth pastes of various pharmaceutical companies were observed with 249.0−250.9 mg/capsule, 249.3−250.7 mg/injection and 0.048%−0.049% in tooth pastes with relative standard deviation (RSD) 0.2%−5.0% (n = 3). Key words: tranexamic acid; vanillin; spectrophotometry CLC number: R917
Document code: A
Article ID: 0513-4870 (2009) 02-0175-06
Introduction
Materials and methods
Tranexamic acid (TA) is a hydrophilic drug used as an anti-fibrinolytic agent[1, 2] to reduce bleeding after cardiac surgery[3] and arthroplastic surgery[4]. It also exhibits anti-inflammatory[5], whitening effects on skin[6].
Materials and reagents All the chemicals and reagents used were of analytical or pharmaceutical grades. The double distilled water used throughout the study was obtained from distillation plant all made of glass. Pure tranexamic acid (TA), vanillin (VAN) and acetic acid were obtained from E. Merck (Germany), ethanol from BDH (UK) and sodium acetate from Fluka
The prophylactic administration of TA 10 mg·kg−1·h−1 significantly reduced red blood cell transfusion in liver transplantation[7]. Several analytical methods have been reported for the analysis of TA, based on spectrophotometric[8−15], flourimetric[16], thin layer chromatographic[17], ion exchange chromatographic[18], high performance liquid chromatographic[19−26] and gas chromatographic[27, 28] techniques. For spectrophotometric analysis, the determination is carried out using suitable reagents such as 2, 4, 6-trinitrobenzosulfonic acid, p-dimethylaminobenzaldehyde, naphthalene-2,3dicarboxaldehyde, 2-hydroxynaphthaldehyde[10, 11, 14, 20]. The derivatization either increases the molar absorptivity or produces bathochromic shift in the absorbance. Therefore, vanillin (VAN) is examined for the first time as a derivatizing reagent for spectrophotometric determination of TA in various pharmaceutical preparations. Received: 2008-10-08. * Corresponding author Tel: +9222772486, E-mail:
[email protected]
(Switzerland). Buffer solutions between pH 1−10 at unit internal were prepared from hydrochloric acid (1 mol·L−1), potassium chloride (1 mol·L−1 ) (pH 1−2), acetic acid (1 mol·L−1), sodium acetate (1 mol·L−1) (pH 3−6), ammonium acetate (1 mol·L−1) (pH 7), sodium bicarbonate (1 mol·L−1), sodium carbonate (saturated solution) (pH 8−9) and ammonium chloride (1 mol·L−1) and ammonia solution (1 mol·L−1) (pH 10−11). The solution of VAN 1% (w/v) was prepared in distilled water (100 mL). The solution of TA (10 μg·mL−1) was prepared by dissolving 0.001 g TA in double distilled water (100 mL). The spectrophotometric studies were carried out with a double beam spectrophotometer UV-1601 (Shimadzu Corporation, Japan) with dual silica 1cm cuvettes. Analytical procedure The aqueous solution (0.5−2.5 mL) containing TA (5−25 µg) was transferred
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药学学报 Acta Pharmaceutica Sinica 2009, 44 (2): 175−180
to 10 mL calibrated stoppered volumetric flasks and were added 3 mL VAN in double distilled water 1% (w/v), followed by HCl-KCl buffer pH 1 (1 mL). The contents were heated on water bath at (90±5) ℃ for 15 min. The solutions were cooled at room temperature and the volumes were adjusted to mark with ethanol. The absorbance was measured at λmax 354 nm against reagent blank which was prepared in a similar way by omitting the addition of TA. UV method un-derivatized The aqueous solution (0.5−2.5 mL) containing TA (500−2 500 µg) was transferred to 10 mL calibrated stoppered volumetric flasks and the volumes were adjusted to mark with ethanol. The absorbance was measured at λmax 207 nm against ethanol. The molar absorptivity was observed 739 L·mol −1·cm−1. Analysis of TA from capsules dosage form For the analysis of TA contents from capsules, thirteen samples of different pharmaceutical companies were collected. The sample (0.25 g) from well ground mixture of at least five capsules of each of the following sample: Aneptil (Alina Combine (Pvt) Ltd. Karachi, Pakistan), Btrol (Bosch Pharmaceuticals (Pvt) Ltd. Karachi, Pakistan), Haematrix (Macter International (Pvt) Ltd. Karachi, Pakistan), Maxna (Ali Gohar Pharmaceuticals (Pvt) Ltd. Karachi, Pakistan), Ranmic (Medicraft Pharmaceutical (Pvt) Ltd. Lahore, Pakistan), Transamin (Hilton Pharma (Pvt) Ltd. Karachi, Pakistan), Transcam (Chas A.Mendoza Karachi, Pakistan), Tranxic (Lisko Pakistan (Pvt) Ltd. Karachi, Pakistan), Traumax (Siza International (Pvt) Ltd. Lahore, Pakistan), Traxyl (Organon Pakistan (Pvt) Ltd. Karachi, Pakistan), Xamig (Highnoon Laboratories, (Pvt) Ltd. Lahore, Pakistan), Xed (Indus Pharma (Pvt) Ltd. Karachi, Pakistan), Zatranex (Zafa Pharmaceutical Laboratories (Pvt) Ltd. Karachi, Pakistan) was dissolved in 100 mL of double distilled water. The solution 0.1 mL was further diluted up to 25 mL with double distilled water. The solution (1 mL) was transferred to volumetric flask (10 mL) and the procedure described in “Analytical procedure” was followed. Analysis of TA from injections dosage form For the analysis of TA contents from ten injections of different pharmaceutical companies, the sample (5 mL) from each of the TA injection: B-STOP (Saydon Pharmaceuticals Industry (Pvt) Ltd. Peshawar, Pakistan), Haematrix (Macter International (Pvt) Ltd.
Karachi, Pakistan), Maxna (Ali Gohar Pharmaceuticals (Pvt) Ltd. Karachi, Pakistan), Tranamin (Akson Pharmaceutical Company (Pvt) Ltd. Mirpur, Azad Kashmir), Transcam, (Chas A. Mendoza Karachi, Pakistan), Traumax (Siza International (Pvt) Ltd. Lahore, Pakistan), Traxyl (Organon Pakistan (Pvt) Ltd. Karachi, Pakistan), Xamig (Highnoon Laboratories, (Pvt) Ltd. Lahore, Pakistan), Xed (Indus Pharma (Pvt) Ltd. Karachi, Pakistan), and Zatranex (Zafa Pharmaceutical Laboratories (Pvt) Ltd. Karachi, Pakistan) was diluted up to 100 mL with double distilled water. The solution 0.1 mL was again diluted up to 25 mL with double distilled water. The aqueous dilution (1 mL) was transferred to volumetric flask (10 mL) and the procedure was repeated as described in “Analytical procedure”. Analysis of TA from tooth pastes For the analysis of TA contents from two tooth pastes the sample (10 g) from each of the TA tooth paste, HI-SALZ (Platinum Pharmaceutical (Pvt) Ltd. Karachi, Pakistan), and Xamic (Spirax International (Pvt) Ltd. Karachi, Pakistan), was dissolved in 100 mL double distilled water. The solution was filtered using Whatmann No. 01 filter paper and 5 mL was again diluted up to 25 mL with double distilled water. The aqueous dilution (1 mL) was transferred to volumetric flask (10 mL) and the procedure was repeated as described in “Analytical procedure”. Recovery (%) of TA from samples by standard addition Each pharmaceutical preparation was prepared as above mentioned procedures for the analysis of TA from dosage forms. Two portions from each consisting of 1 mL were taken in two different volumetric flasks (10 mL). A solution from each proceeded as described in “Analytical procedure” and other was added 5 μg of TA. The solution again proceeded as “Analytical procedure”.
Results and discussion Tranexamic acid (TA) (4-aminomethyl cyclohexanecarboxylic acid) reacts with vanillin (VAN) to form an azomethine derivative 4-{[(4-hydroxy-3-methoxybenzylidene)-amino]-methyl}-cyclohexanecarboxylic acid (TA-VAN) (Figure 1) which absorbs maximally with bathochromic shift to 354 nm with molar absorptivity of 25 160 L·mol−1·cm−1. VAN was then examined as a derivatizing reagent for the spectrophotometric determination of TA. The effects of pH, amount of
F.M.A. Rind, et al: Spectrophotometric determination of tranexamic acid using vanillin
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VAN added, heating time and temperature on the formation of (TA-VAN) derivative were studied.
Figure 2 Effect of volume of 1% reagent on the absorbance of TA derivative
Figure 1 Formation of TA derivative using vanillin as derivatizing reagent
1 Optimization of parameters 1.1 Analytical wavelength For the quantitative analysis, the wavelength of maximum absorbance plays an important role. It is necessary to check that derivatizing reagent should not absorb close to the region where the analyte derivative absorbs. This may cause error in absorption of the drug because the derivatizing reagent is added in excess to complete the reaction quantitatively. To avoid this problem, it is necessary to select the wavelength where the derivatizing reagent indicates minimum absorbance and the analyte derivative shows maximum absorbance value. The absorbance value of 1 µg·mL−1 of TA as VAN derivative was recorded at different wavelengths between 250−500 nm after heating for 15 min at 90 ℃ using buffer pH 1. The maximum absorbance occurred at 354 nm against reagent blank and was selected as optimum. 1.2 Effect of reagent volume The effects of adding various volumes of VAN solution on absorbance of 2 µg·mL−1 TA are given in Figure 2. The volumes of reagent 1% aqueous VAN were varied between 1−4 mL with an interval of 1 mL and the absorbance was measured at λmax 354 nm. The similar absorbance was observed with addition of 2−3 mL therefore the addition of 3 mL 1% (w/v) VAN aqueous solution was selected. 1.3 Effect of order of mixing the reagents The order of adding reagents during derivatization process has important role in accuracy of results and enhancement of absorbance. In the present study, it was observed that the addition of buffer pH 1 (1 mL) to TA solution (1 mL) followed by the 3 mL VAN reagent 1% (w/v) resulted in a decrease in absorbance value. Taking
the reagent first and then adding the buffer, followed by TA solution also decreased the absorbance value. The maximum absorbance value was observed when 3 mL of reagent VAN was added to the standard solution of TA followed by buffer (1 mL) pH 1. The contents were then heated on water bath and the volume was adjusted to 10 mL with ethanol. 1.4 Optimization of heating time and temperature for the formation of derivative To achieve the maximum absorbance value for an analyte by the formation of stable derivative, the selection of optimum time and temperature is essential. The effect of time on the formation of derivative in terms of absorbance of 1 µg·mL−1 TA solution in the presence of 1% VAN solution was checked at 354 nm from 0−30 min with an interval of 5 min. A similar absorbance was observed after heating for 15 min. Therefore, the heating time of 15 min at 90 ℃ was considered as optimal. 1.5 Effects of solvents The effects of various solvents such as toluene, cyclohexane, acetone, carbon tetrachloride, acetonitrile, methanol, 1-propanol, isopropanol, 1-butanol, amyl alcohol, isoamyl alcohol, 1,4-diaxone, ethyl acetate and nitrobenzene on the absorbance of 1 µg·mL−1 TA using VAN as a derivatizing agent were examined. From each of the solvents 1 and 2 mL was added after the addition of 1% aqueous solution of VAN, and 1 mL HCl-KCl buffer (pH 1) followed by heating for 15 min at 90 ℃. Ethanol proved to be the best choice. 1.6 Effect of pH The effect of adding 1 mL of 1 mol·L−1 buffers of pH range 1-10 on the absorbance of 2 µg·mL−1 TA solution was studied at optimized conditions. It is evident from Figure 3 that the maximum absorbance was observed at buffer pH 1 and addition of buffers pH 2 to pH 8 decreased the absorbance. Addition of buffer of pH 9 and above produced precipitation. Therefore, the HCl-KCl buffer of pH 1 was selected as optimal.
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药学学报 Acta Pharmaceutica Sinica 2009, 44 (2): 175−180 Table 1 Analysis of TA from capsules (Amount labeled 250 mg/capsule) Amount found Relative Recovery mg/capsule RSD/% deviation from /% labeled value/% (Standard deviation)
Name of preparation
Figure 3
Effect of pH on derivatization of TA
2
Interference study The effect of possible presence of associated materials such as sodium chloride, mannitol, sorbitol, lactose, sucrose, glucose, galactose and fructose was investigated at 10 times the concentration of TA and it was observed that none of these substances interfered with change in absorbance of within ± 4%. 3 Stability of the derivative The stability of TA-VAN derivative was examined but no change in absorbance more than 5% was observed within 48 h. 4 Calibration plot The effect of variation in the concentration of TA on its absorbance was studied. A linear calibration curve was obtained which obeyed the Beer’s law within
Aneptil
249.0 (1.0)
0.40
0.40
96.0
Btrol
249.9 (1.0)
0.40
0.04
97.8
Haematrix
250.3 (0.6)
0.23
0.12
99.0
Maxna
249.0 (2.6)
0.86
0.40
99.6
Ranmic
250.1 (2.2)
1.06
0.06
98.4
Transamin
249.3 (2.1)
0.83
0.26
100
Transcam
250.1 (1.0)
0.41
0.04
96.8
Tranxic
249.5 (2.7)
1.06
0.84
98.0
Traumax
250.3 (3.3)
1.30
0.12
96.5
Traxyl
249.9 (2.2)
0.86
0.02
99.9
Xamig
251.0 (1.0)
0.40
0.40
98.3
Xed
250.6 (2.1)
0.85
0.25
99.6
Zatranex
250.9 (1.0)
0.42
0.38
95.8
Table 2 Analysis of TA from injections(Amount labeled 250 mg/ injection) Amount found Relative Recovery mg/injection RSD/% deviation from /% labeled value/% (Standard deviation)
Name of preparation B-STOP
250.5 (0.5)
0.96
0.20
99.0
Haematrix
250.4 (0.6)
0.25
0.16
98.8
Maxna
250.6 (1.1)
0.43
0.27
95.5
Tranamin
250.2 (0.4)
0.17
0.08
95.6
Transcam
250.1 (0.5)
0.22
0.04
96.0
Traumax
249.3 (2.1)
0.83
0.26
100
the concentration range 0.5−2.5 µg·mL of TA with coefficient of determination r2 0.999 7 (Figure 4). The sandells sensitivity (0.004) was observed at 0.05
Traxyl
250.4 (0.6)
0.23
0.18
96.8
Xamig
250.3 (1.5)
0.61
0.12
97.0
Xed
250.3 (2.1)
0.85
0.14
99.5
μg·mL−1 TA. The validity of the calibration curve was obtained by the analysis of test solutions of TA (n = 4)
Zatranex
250.7 (0.6)
0.25
0.28
99.9
−1
Table 3
and the percent relative error was found ± 1%−2%. The recovery calculated by standard addition was within the range 96%−99% with RSD 0.2%−5.0%. The pharmaceutical preparations containing TA available in the local market were analyzed to determine the amount of TA quantitatively (Table 1−3).
Analysis of TA from tooth pastes
S. No. Name of preparation
HI-SALZ
02 Xamic
Amount labeled /% (w/w)
0.05
0.05
Amount found /% (Standard deviation)
0.049 (1.15)
0.048 (2.51)
RSD/% Relative deviation from labeled value (± %) Recovery/%
Figure 4 Calibration curve of tranexamic acid 0.001% using vanillin as a derivatizing reagent
01
2.35
5
2
4
95.6
95.0
The mean values at 95% confidence limit of TA capsules from thirteen pharmaceutical brands, injections of ten pharmaceutical brands and tooth pastes of two pharmaceutical brands were (250 ± 0.207 4) mg/capsule, (250.4 ± 0.018 41) mg/injection and (0.048 5 ± 0.000 74)% per tooth paste, respectively (Table 4).
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F.M.A. Rind, et al: Spectrophotometric determination of tranexamic acid using vanillin Table 4
Optical characteristics, precision and accuracy Parameter
[2]
Value
Beer’s law limits/µg·mL−1
0.5−2.5
Molar absorptivity/L·mol−1 ·cm−1 Sandells sensitivity (0.004 absorbance unit) /µg·mL−1 Regression equation (y)a Slope (b) Intercept (a) Coefficient of determination
25 157 0.05
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Relative deviation (± %) Mean value mg/capsule ± range of error at (95% confidence limit) of thirteen capsules of various pharmaceutical companies Mean value mg/ampoule ± range of error at (95% confidence limit) of ten ampoules of various pharmaceutical companies Mean value % tooth paste ± range of error at (95% confidence limit) of two tooth pastes of two pharmaceutical companies
Effect of local
tranexamic acid gel in the treatment of epistaxis [J].
0.159 3 0
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179 ·
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Conclusion
tions by derivatization with naphthalene-2, 3-dicarboxaldehyde/
The developed method is simple, accurate, precise, inexpensive and less time consuming. The molar absorptivity of the developed method is much more than un-derivatized UV method and the λmax is considerably higher than this method. This is an important quality of the developed method which is used to avoid the interferences from associated materials which may absorb in the UV region. The method was applied for the determination of TA contents from various pharmaceutical preparations.
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