In vitro tools to simulate the regional differences of the human GI tract Mirko Koziolek Department of Biopharmaceutics & Pharmaceutical Technology Center of Drug Absorption and Transport University of Greifswald, Germany
1st all-WG UNGAP meeting 2018 in Leuven “Regional differences along the GI tract”
Simulation of gastrointestinal conditions in dissolution testing Typical test conditions • large media volumes (900-1000 mL) • static pH and temperature • use of buffer systems such as phosphate or acetate • application of high shear rates, but low shear stresses • often non-sink conditions
Does this reflect real-life conditions? 2
Dynamic conditions inside gastrointestinal tract pH value pressure [mbar] Temperature [°C] 14
I. Stomach
600
III. Colon
II. SI
12
500
45 40 35
10
400
8 300
30 25 20
6 200
4 2
100
0
0
15 10 5
0
4
8
12
16
20
24
28
32
0
36
Time [h] Individual profiles of pH, temperature and pressure measured by SmartPill®.
Koziolek et al. J Control Release (2015)
3
Biorelevant dissolution testing Broad range of different in vitro tools:
• • • • • • •
Dynamic Gastric Model BioGIT dissolution stress test GastroDuo TNO TIM-1 and TIM-2 physio-grad …
4
Biorelevant in vitro tools static
dynamic
monocompartmental
paddle apparatus
GastroDuo Dynamic Gastric Model
multicompartmental
USP apparatus III
TNO TIM-1
5
Biorelevant dissolution media Selection of biorelevant media used to simulate composition of luminal fluids of certain regions of the human GI tract Fasted state
Fed state
Stomach
SGF FaSSGF
FeSSGF Full-fat milk Ensure Plus
Small intestine
FaSSIF FaSSIF-V2
FeSSIF FeSSIF-V2
Colon
FaSSCoF
FeSSCoF
Markopoulos et al. Eur J Pharm Biopharm (2015)
6
Biorelevant dissolution media Levels of complexity of biorelevant media
Schematic figure of the experimental setup in the GastroDuo. 10
GastroDuo Test programs – standard program A Temperature / °C
36 32 28 24 20 16 0
5
10
15 20 Time / min
25
30
0
5
10
15 20 Time / min
25
30
7 6 5
pH
4 3 2 1 0
Test program A (standard program for fasted state) with varying pressure, flow and movement conditions in the GastroDuo. Sager et al. PBP World Meeting 2018
11
GastroDuo Test programs Description A
standard program
B
no initial pressure event
C
short gastric transit (15 min)
D
long gastric transit (45 min)
E
constant temperature (37°C)
F
constant pH (pH 1.2) Test program A with varying pressure, flow and movement conditions in the GastroDuo.
Sager et al. PBP World Meeting 2018
12
GastroDuo Drug release from hard gelatin capsules
Cumulative caffeine release in the acceptor vessel (means, n=6 ± SD). Sager et al. PBP World Meeting 2018
13
Small intestine – physiological considerations • • • • •
limited fluid volumes1 formation of micellar structures2 antro-duodenal pH change drug absorption motility
1Schiller
et al. Aliment Pharmacol Ther (2005), 2Porter et al. Nat Rev Drug Discov (2007)
14
Small intestine – biorelevant in vitro methods In vitro tools: • Mini paddle dissolution test for the simulation of the conditions in the ileum • transfer model • Bio-GIT • Gastrointestinal Simulator (GIS) • TNO TIM-1 Biorelevant dissolution media: • Fasted State Simulated Intestinal Fluid (FaSSIF) • Fed State Simulated Intestinal Fluid (FeSSIF) • enhanced versions of FaSSIF/FeSSIF 15
Changes during antro-duodenal transit
GE
8 7 pH value
6 5 4 3 2 1 0 3.0
3.2 3.1 time / h
3.3
16
Simulation of antro-duodenal transfer • • • •
Artificial stomach-duodenum (ASD) model BioGIT Gastrointestinal Simulator (GIS) Tiny-TIM
Biorelevant gastrointestinal transfer (BioGIT) model
Kourentas et al. Eur J Pharm Sci (2016)
17
Small intestine – Simulation of drug absorption either separate absorption modules or integrated into dissolution test • cell and tissue based models monolayers of Caco-2 cells or MDCK cells porcine intestinal mucosa or rat intestine
• models based on artificial membranes or filters µFlux (PVDF membrane) MacroFlux permeation bag dialysis cells
• biphasic dissolution tests • ... 18
Colon – physiological considerations • • • •
variable pH values limited amount of fluid variable transit times complex microbiom
19
Colon – Biorelevant in vitro methods In vitro tools: typically used for metabolization studies • batch fermenters (static or semi-dynamic) • MimiCol • TNO TIM-2
Biorelevant media: • FaSSCoF/FeSSCoF • addition of specific enzymes (e.g. pectinase, amylases) • addition of rat caecal contents or human fecal slurrry 20
Simulation of GI transit of dosage forms
Dissolution Stress Test Apparatus • • • •
alternating phases of stress and rest high pressure events and high velocities hydrodynamics inhomogenous fluid distribution
Garbacz et al. Eur J Pharm Biopharm (2008)
22
B
Applied Test Algorithms Stomach
A 0
1
Small Intestine
B time (h)
Colon Colon
A
A
A
A
5
7
9
11
High stress phase 3 Pressure waves of 300 mBar per 6 s, (duty cycle 50%) + 1 min rotation at 100 rpm
A
Mild intestinal transit B
Every 10 min: 0,5 min rotation at 10 rpm
Garbacz et al. AAPS PharmSciTech 2014
24
Dissolution Stress Test Drug release from quetiapine 50 mg ER tablets Ileocaecal valve
50
drug dissolved (mg)
40
Pylorus
30 20 Stress Test PP pH 6.8 USP II PP pH 6.8
10 0 0
4
8
12
16
20
24
time (h) Garbacz et al. AAPS PharmSciTech 2014
25
Simulation of GI pH profiles How can we simulate dynamic pH profiles?
subject 1-3
Koziolek et al. J Pharm Sci 2014.
26
Simulation of GI pH profiles Semi-dynamic simulation of gastrointestinal pH values in USP apparatus III
Tablets Klein S et al. J Pharm Pharmacol (2005), Klein S. Pharmazie (2015)
Pellets 27
Simulation of pH profiles
N2
CO2
Intestinal media based on physiological buffers - in vitro setup
pH electrode gas diffusor
pH 6.80 pH ysio-grad® 3/2 way solenoid valve
Garbacz G et al. Eur J Pharm Sci (2014)
28
Simulation of pH profiles Fasted GI passages in individual patients
Karkossa & Klein J Pharm Sci (2018)
29
Simulation of pH profiles Tablets versus pellets – Mesalazine MR
Karkossa & Klein J Pharm Sci (2018)
30
Complex simulation of human GI physiology - TNO TIM-1 Simulation of: • body temperature • peristalsis • gastrointestinal pH profiles • GI transit times • secretion of gastric acid and salivary/gastric enzymes • secretion of bile and pancreatic juice • drug absorption
31
Biorelevant in vitro tools Which aspects need further consideration? • certain physicochemical parameters of luminal fluids (e.g. viscosity) • digestive processes (e.g. human gastric lipase) in stomach and small intestine • simulation of absorption • simulation of the action of colonic microbiota
need for in vivo data of high quality
32
Implementation of in vivo data Simulation of human gastric motility
pH value pressure [mbar] Temperature [°C] 14
600
12
500
45 40 35
10
400
8 300
30 25 20
6 200
4 2
100
0
0
15 10 5
0
4
8
12
16
20
24
28
32
0
36
Time [h]
SmartPill data
GastroDuo
33
Implementation of realistic motility scenarios In vivo data
In vitro simulation
Schneider et al. Eur J Pharm Sci (2017)
34
Physiologically relevant models used in Food Science and Technology • • • •
Digestive Cell (U Leeds) Human Gastric Simulator (UC Davis) SHIME Dynamic Duodenal Model (U Birmingham)
35
Thank you for your attention! Acknowledgement University of Greifswald Werner Weitschies Michael Grimm Felix Schneider Philipp Jedamzik Maximilian Sager Regine Beeck Gunnar Glöckl
Center of Drug Absorption and Transport, Greifswald
Sandra Klein Frank Karkossa Physiolution GmbH Grzegorz Garbacz