Oral Formulations for Poorly Water Soluble Compounds. SAQ - Fachgruppe Pharma & Chemie Oskar Kalb, Novartis Pharma AG Basel Olten, 23.

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1 Oral Formulations for Poorly Water Soluble Compounds SAQ - Fachgruppe Pharma & Chemie Oskar Kalb, Novartis Pharma AG Basel Olten, 23. June 2009

2 Oral Delivery of Poorly Water Soluble Compounds For systemic activity of an API molecule after oral administration it must be absorbed from the intestine and reach the bloodstream / the site of action Passive diffusion is the most dominant mechanism of drug absorption from the intestinal lumen (GIT) from. P. D. Ward et.al. Pharmaceutical Sciences and Technology Today Vol. 3, No.10 Oct Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

3 Oral Delivery of Poorly Water Soluble Compounds Disintegration Dissolution Absorption Systemic circulation Tablet Powder Solution With a few exceptions, molecular dispersion of a drug is a prerequisite for its absorption across biological membrans This dictates that after oral administration the drug has to dissolve in the gastrointestinal fluid before partitioning into and across the enterocyte This implies that the dissolution of a poorly water soluble drug can become the rate limiting step for the onset of drug levels in the blood (if absorption is reasonable fast) Negative impact on Oral Bioavailability 3 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

4 Drug Dissolution Noyes Whitney dx/dt Dissolution rate A Interfacial surface area D Diffusion coefficient h Thickness of diffusion layer Xd Amount of drug dissolved Cs Saturation solubility V Volume of dissolution medium Key parameter that influence dissolution rate Solubility of the API - Polymorph, pka, Gastro-intestinal ph, Buffer Capacity of the GIT Surface area (A) - Particle size, wetting properties Physico-chemical properties of the API AND the physiological state of the GIT can have a significant impact on the in-vivo dissolution of the drug 4 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

5 Dose and Dose number (D 0 ) Solubility and Dose always have to be considered together D o = M o /V o C s M o V o C s = dose administered (mg) = 250 ml (reference volume of human stomach, FDA-approach) = solubility (mg/ml) Remarks: D o = > 20 at pharmacological doses -> already critical In practice, D o values often between 20 and 100 for pharmacological and human doses. For TOX doses, D o up to 1000 and more are frequent! 5 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

6 Absolute bioavailability vs. variability Inverse relationship between the absolute bioavailability (F) of an oral dosage form and it s total intersubject variability (CV). From Hellriegel E.T et al. Clin. Phamacol. Ther. 1996; 60: To lower the variability means for a formulation scientist in most cases to improve the bioavailability in the fasted state 6 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

7 Biopharmaceutical Classification Scheme Solubility and Permeability are key determinant of oral bioavailability Biopharmaceutical Classification System Class II Low solub High perm Class I High solub High perm Class II Formulation Class I Class IV Low solub Low perm Class III High solub Low perm Class IV Class III Limited formulation influence 7 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

8 Use of Drug Delivery Systems in Major Pharmaceutical Companies Distribution with regard to route of administration 50% 40% 30% 20% 10% 0% Oral 47% Parenteral 18% 16% 11% Inhalation Source: Kermani, F., et.al., Drug Delivery Technology, Oct Transdermal Other 8% 8 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

9 Approaches to improve Solubility, Dissolution of poorly water soluble APIs and decrease Variability 1. Physical modifications Particle size reduction (Nanosuspensions, micronization) Dispersion of drug in a polymer matrix (Solid Dispersions, solid solutions) Polymorphs / Pseudopolymorphs Complexation / Solubilization 2. Lipid-based systems e.g. Microemulsions (SMEDDS) 9 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

10 Examples Impact of a particle size reduction on dissolution and oral bioavailability of a poorly water soluble drug Nanosuspenions 10 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

11 I. Nanosuspensions Working principle Increased dissolution rate by reducing particle size to the nanometer range (and thereby increasing the surface area) Noyes Whitney (modified) Technology Downstream Process (e.g. Milling) Up-stream Process (e.g. Precipitation) Drying of nanosuspension Solid Dosage Form 11 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

I. Nanosuspensions Nanosizing Most prominent manufacturing technology (e.g. NanoCrystal wet milling technology by Elan) Addition of stabilizers (polymers, surfactants) to prevent agglomeration of nanosized particles Ref.

12 I. Nanosuspensions Nanosizing Most prominent manufacturing technology (e.g. NanoCrystal wet milling technology by Elan) Addition of stabilizers (polymers, surfactants) to prevent agglomeration of nanosized particles Ref. E. Merisko-Liversidge et.al. Eur. J. Pharm.Sci. 18 (2003), Particle size distribution of Naproxen crystals before milling (triangle, mean 24.2 um) and after milling (circle um) 12 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

13 I. Nanosuspensions Impact of particle size reduction on dissolution rate Example: Cilostazol (BCS II) Particle size (median) - Hammer-milled ( ) 13 μm - Jet-milled ( ) 2.4 μm - NanoCrystal ( ) 0.2 μm Dissolution rate testing - water 37 C, 900ml - 50rpm, USP apparatus 2-5 mg cilostazol Ref. Jinno J. J. Contr. Rel. 2006; 111:56-64 Dissolution rate of Cilostazol from a suspension is clearly increased by a reduction of the drug substance particle size 13 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

14 I. Nanosuspensions Pharmacokinetic of Cilostazol suspensions in fasted and fed beagle dogs Ref. Jinno J. J. Contr. Rel. 2006; 111:56-64 (C) Hammer-milled ( ) (B) Jet-milled (A) NanoCrystal ( ) ( ) D Serum concentration vs. time after oral administration of cilostazol suspensions (100mg/body) in fasted (open) and fed (closed) beagle dogs (n=4) (mean; SD) Major increase in bioavailability with minimal food effect observed for the Cilostazol nanosuspension (NanoCrystal ) 14 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

15 Examples Impact of a formulation parameter on oral bioavailability of a poorly soluble compound Solid dispersion 15 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

16 II. Solid Dispersions Definition A poorly water soluble drug that is highly dispersed and stabilized in a hydrophilic carrier Working principle Ultimate particle size reduction No crystal structure Hydrophilic carrier improved wetting of the drug inhibits recrystalization/precipitation of supersaturated solution Surfactant (optional) increase solubilization of the drug 16 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

17 II. Solid Dispersions Oral Absorption of Poorly Water Soluble Drugs Melting Meltextrusion Solid Dispersions NOT bioavailable Organic Solution Solvent evaporation Bioavailable 17 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

18 II. Solid Dispersions In-vitro dissolution rate and in-vivo pharmacokinetic data of NVS02 (BCSII) Dissolution rate Water, 0.1% SDS (20mg NVS02) Fasted dogs, 20mg/animal (n=8) - Crystaline drug - Amorphous drug - Solid Dispersion - Solid Dispersion with 10% SDS Same rank order of tested formulations in in-vitro dissolution rate and in-vivo plasma level curves 18 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

19 II. Solid Dispersions Impact of surfactant on pharmacokinetic of NVS02 (BCSII) Arithmetic mean ± SD whole blood concentration of NVS02 following administration of 30 mg tablets in healthy volunteers (n=18) 80 Whole blood concentration (ng/ml) Solid Dispersion - Polox. +10% Polox. AUC 0- AUC [ng h/ml] 214 (97) 296 (130) CV % C max 28 (9) 72 (16) CV % t max Time post-dose (h) 30 SD mg ASM981 with 10% (MF, fasted, surfactant 2 x 15 mg) 30 SD mg ASM981 without (FMI, surfactant fasted, 1 x 30 mg) The formulation containing a surfactant showed a higher and less variable absorption of the drug from the GIT 19 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

20 II. Solid Dispersions Physical and chemical stability 100 % time (years) chemical degradation physical stability of amorphous state RISK: Recrystalization of amorphous drug during storage 20 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

21 II. Solid Dispersions Pharmacokinetics of NVS02 solid dispersions (with diff. % of crystalline DS) Single dose, 3-arms, crossover study in fasted dogs (n=9) NVS02 NKP608 plasma concentration in in ng/ml ng/ml HH SD-tablet, 100% amorphous drug GG SD-tablet, 70% amorphous drug EE SD-tablet, 50% amorphous drug Time (hours) Data indicate that exposure is significantly reduced when drug crystalizes out during storage of the solid dispersion Physical stability can cause significant variability in pharmacokinetics of solid dispersions 21 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

22 Example Formulation approach for a lipophilic, poorly water soluble drug Microemulsion 22 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

III. Lipid based formulations Enhancement of oral absorption of poorly water soluble drugs (PWSD) SOLUBILIZATION permeation 1. Increasing solubilization and drug disposition in the intestinal lumen 2.

23 III. Lipid based formulations Enhancement of oral absorption of poorly water soluble drugs (PWSD) SOLUBILIZATION permeation 1. Increasing solubilization and drug disposition in the intestinal lumen 2. Affecting absorption pathway of drug transport to the systemic circulation 3. Interacting with enterocytebased transport and metabolic processes Fig from Porter CJH et al., Nature Reviews Drug Discovery, Vol. 6, March 2007, Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

24 III. Lipid based formulations Increasing solubilization and drug disposition in the intestinal lumen Digestion of exogenous lipids by pancreatic enzymes (lipase, co-lipase) TG DG MG + FA Formation of colloidal structures with endogenous bilary lipids Increase solubilization capacity for lipid digestion products and drugs in the small intestine Fig from Porter CJH et al., Nature Reviews Drug Discovery, Vol. 6, March 2007, Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

III. Lipid based formulations In-vivo performance Risk: Precipitation on Dispersion of the formulation Lipid-based formulations must maintain drug in solution in the GIT to enhance oral

25 III. Lipid based formulations In-vivo performance Risk: Precipitation on Dispersion of the formulation Lipid-based formulations must maintain drug in solution in the GIT to enhance oral bioavailability Risk: Precipitation on Digestion of the formulation Fig from Porter CJH et al., Nature Reviews Drug Discovery, Vol. 6, March 2007, Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

26 III. Lipid based systems Micellular systems, Microemulsions, Emulsions Micelle (o/w) nm (< 200 nm) Microemulsion (o/w): Thermodynamically stable Translucent, isotropic Up to a few µm Emulsion (o/w): Thermodynamically unstable Milky apperance 26 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

III. Lipid based systems: Microemulsions: Phase diagram screening Potential formulations Hydrophilic phase Surfactant I00% 90 10 80 20 70 30 60 40 50 50 40 60 30 70 20 80 10 90 I00% 90 80 70 60 50 40

27 III. Lipid based systems: Microemulsions: Phase diagram screening Potential formulations Hydrophilic phase Surfactant I00% I00% I00% Lipophilic phase Undiluted Preconcentrate Clear, homogenous formulation No precipitation with a reasonable drug loading Diluted Self-dispersing Stable and no precipitation in physiological relevant time frame 27 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

III. Lipid based Systems Oral Absorption of

bioavailable Bioavailable 28 Drug Delivery

28 III. Lipid based Systems Oral Absorption of Poorly Water Soluble Drugs Solubilisation Encapsulation Microemulsion Organic or lipidbased solutions Filling NOT bioavailable Bioavailable 28 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

the microemulsion 29 Drug Delivery Systems

29 III. Lipid based formulations From Preconcentrate to the Microemulsion Soft gel capsule filled with microemulsion preconcentrate Water In-situ formation of the microemulsion 29 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

30 III. Lipid-based formulations Cyclosporine A Cyclosporine A Cyclic petide (containing 11 aminoacids) Lipophilic, low aqueous solubility (< 0.004% w/v) Higher solubility in lipids (olive oil >4%) and ethanol (~10%) 30 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

Cyclosporine drug substance Sandimmun Sandimmun Neoral 31 Drug

31 III. Lipid based formulations Cyclosporine vs. Sandimmun vs. Sandimmun Neoral Prior to dilution with water Diluted with water Cyclosporine drug substance Sandimmun Sandimmun Neoral 31 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

32 III. Lipid based formulations Sandimmun vs. Sandimmune Neoral - Pharmacokinetic data Concentration (ng/ml) Sandimmun Concentration (ng/ml) Sandimmun Neoral Time (h) Concentration-time profiles following single oral administration of 300 mg Sandimmun to 24 volunteers J.M. Kovarik et al., Journal of Pharmaceutical Sciences, 83 (3), Time (h) Concentration-time profiles following single oral administration of 180 mg Sandimmun Neoral to 24 volunteers Sandimmun : Adsorption is dependent on digestion of the lipid-formulation solubilization depends on individual physiological state in the GIT (e.g. food intake, bile flow) high inter- and intra-subject variability Sandimmun Neoral : Spontaneous formation of the microemulsion in the GIT without the need of endogenous compounds like bile salts / phospholipids significant reduction of dose as well as inter-, and intra-subject variability 32 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

III. Lipid based formulations Lipid digestion models for in-vitro assessment lipid-based formulations Undispersed oil phase containing drug (D) Aqueous phase containing drug solubilized in micellar

33 III. Lipid based formulations Lipid digestion models for in-vitro assessment lipid-based formulations Undispersed oil phase containing drug (D) Aqueous phase containing drug solubilized in micellar and vesicular structures, Pellet phase containing precipitated drug and insoluble (calcium) soaps of FA Sek L et al., J. Pharm. Pharmacol., 2002, 54:29-41 Porter CJH et al., Nature Reviews Drug Discovery, 2007, 6: Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

34 III. Lipid based formulations In vitro digestion test to evaluate solubilization pattern after digestion Concentration (ng/ml) Sandimmun Concentration (ng/ml) Sandimmun Neoral Time (h) Time (h) % modelpwsd Fasted Fed % in undigested phase % in aqueous phase % in pellet phase % model PWSD Fasted Fed % in aqueous phase % in pellet phase Digestion phases Digestion phases Digestion needed to release and Similar solubilization pattern in maintain drug in the aequous solution fasted and fed state 34 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009 Ref: Taillardat A. et al. Am. Pharm Rev (6):40-46

35 Examples Improved oral bioavailability of a weakly basic drug ph-modified Formulations 35 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

36 IV. ph-modified Formulations Improved bioavailability of weakly basic drugs by modulating the micro-ph Stomach (fasted): ph 1-2 Intestine (fasted): ph 5-6 Dipyridamole solubility [mg/ml] CH 2 OH CH 2 OH N N N N N N N N CH 2 OH CH 2 OH Dipyridamole: Solubility ph= mg/ml ph= mg/ml ph Gastrointestinal ph is influenced by several factors (e.g. food, age) intra-, intersubject variability ph-modified Formulation: Incorporation of acids to improve dissolution of weakly basic drugs 36 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

37 IV. ph-modified Formulations Effect of different ph-modifier (20%) on release rate of Dypyridamol tablets Dissolution in phosphate buffer ph 6.8, SDS 0.1% Drug release [%] FA CA SA AA no acid Time [min] Acid type pk a1 pk a2 pk a3 Solubility Fumaric acid (FA) Citric acid (CA) Succinic acid (SA) Ascorbic acid (AA) (Ref. Siepe S. et.al. PhD-thesis 2005) Acidic strength and solubility of the acids have an impact on drug release Fumaric acid selected due to most favourable phys.-chem. properties 37 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

38 IV. ph-modified Formulations Dissolution rate of NVS05 (20%) ph-modified tablets (monolytic-, mini-tablets) Solubility profile NVS05 Dissolution rate in phosphate buffer ph 6.8, SDS 0.1% Monolytic tablet (d=10mm) Minitablets (d=2mm) Solubility [g/l] ph Drug release [%] FA 20% FA 40% Without acid Time [min] Drug release [%] Without acid FA 20% Time [min] Optimal drug to ph-modifier ratio (1:1) (Ref. Siepe S. et.al. PhD-thesis 2005) Dissolution rate: minitablets > monolytic tablets 38 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

39 IV. ph modified Formulations In-vivo study in fasted, gastric-acidity controlled beagle dogs (n=6) Plasma level AUC 0-24h Variability NVS5 NVR1 plasma concentration [ng/ml] Tablet without FA Tablets with FA Minitablet without FA Minitablet with FA CV [%] Tablets without FA Tablets with FA Minitablets without FA A A-FA B B-FA Minitablets with FA Time [h] Formulation (Ref. Siepe S. et.al. PhD-thesis 2005) The incorporation of an acidic ph-modifier improved oral bioavailability of a weakly basic drug (exposure, variability) Intersubject variability of multiparticulates < monolytic tablet 39 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

40 Summary Several formulation approaches are available to improve the dissolution rate of poorly water soluble compounds To identify the most appropriate formulation principles the drug substance properties, the pharmacological dose (range) and physiological state have to be considered In-vitro and in-silico tools should be fully utilized to select the most appropriate technology / formulation variant Today in-vivo studies for a final proof of concept are still needed 40 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

41 Thanks to Dieter Becker Jean Cuine Anke Diederich Bruno Galli Michael Juhnke Martin Mueller-Zsigmondy Stefanie Siepe Agnes Taillardat Carsten Timpe 41 Drug Delivery Systems for PWSD Oskar Kalb SAQ Conference, Olten, 23. June 2009

Biopharmaceutics Dosage form factors influencing bioavailability Lec:5

Biopharmaceutics Dosage form factors influencing bioavailability Lec:5 Ali Y Ali BSc Pharmacy MSc Industrial Pharmaceutical Sciences Dept. of Pharmaceutics School of Pharmacy University of Sulaimani 09/01/2019