1. 1 TG Dekker – WHO, Malaysia Feb 2005 Comparative dissolution testing and applications World Health Organization Training Workshop on Pharmaceutical Quality, GMP and Bioequivalence Kiev - Ukraine 3 to 7 October 2005 Theo Dekker, D.Sc., consultant to WHO Research Institute for Industrial Pharmacy North-West University, Potchefstroom, South Africa iiftgd@puk.ac.za

2. 2 TG Dekker – WHO, Malaysia Feb 2005 What is dissolution testing? tablets and capsules (conventional)  It measures the portion (%) of the API that (1) has been released from tablets/capsules and (2) has dissolved in the dissolution medium during controlled testing conditions within a defined period  The tablet thus first disintegrates  Then the API will be able to dissolve  Slow disintegration ➜ slow dissolution  The % API dissolved is determined with an appropriate validated method: UV/VIS, HPLC, AA, GC, etc  Dissolution testing is also applicable to suspensions and suppositories

3. 3 TG Dekker – WHO, Malaysia Feb 2005 Glossary Solid oral dosage forms Immediate release typically means that 75% of the API is dissolved within 45 minutes  Rapidly dissolving: ≥ 85% in ≤ 30 minutes  Very rapidly dissolving: ≥ 85% in ≤ 15 minutes Not part of presentation Modified-release dosage forms (consult Int.Ph., BP, USP)  Formulation deliberately changes release (slows down) Extended-release (prolonged-release) Slower release throughout the GI tract Delayed-release (enteric coated tablets) Resists gastric fluid & disintegrates in intestinal fluid

4. 4 TG Dekker – WHO, Malaysia Feb 2005 What is multi-point dissolution? In multipoint dissolution  multiple (≥ 3) samples are withdrawn from the dissolution medium during dissolution testing  at pre-determined time points and  each sample is analysed for the % API dissolved  A graph of % API dissolved against time: The dissolution profile

5. 5 TG Dekker – WHO, Malaysia Feb 2005 Multi-point dissolution Example of dissolution profile

6. 6 TG Dekker – WHO, Malaysia Feb 2005 Comparative dissolution testing The principle  Two or more products or batches containing the same API are compared  The strength of products / batches may or may not be the same (depending on purpose of test)  The dissolution conditions are similar, e.g. Apparatus, medium, volume, rotation speed & temp. Minimize possible experimental differences in conditions  Samples are taken at the same time points and the data (dissolution profiles) compared  Calculations: correct for volume change of dissolution medium

7. 7 TG Dekker – WHO, Malaysia Feb 2005 Comparative dissolution testing Profile similarity determination Two conditions to determine if the dissolution profiles of two products/batches in a particular dissolution medium are similar: 1.If both the test and reference product show more than 85% dissolution within 15 minutes, the profiles are considered to be similar No calculations are required If this is not the case, apply point 2 2.Calculate the f 2 value (similarity factor): If f 2 ≥ 50, the profiles are normally regarded similar

8. 8 TG Dekker – WHO, Malaysia Feb 2005 Comparative dissolution testing Similarity factor f 2 n = number of time points R(t) = mean % API dissolved of reference product at time point x T(t) = mean % API dissolved of test product at time point x  Minimum of 3 time points (zero excluded)  12 units (each in own dissolution vessel) for each product (for “official” purposes)  Only one measurement should be considered after both products have reached 85 % dissolution  RSD at higher time points ≤ 10%

9. 9 TG Dekker – WHO, Malaysia Feb 2005 Comparative dissolution testing Dissolution conditions (study design) Apparatus (choice) Paddle, 50 (75) rpm or Basket, 100 rpm Dissolution media All three media for full comparison 1.Buffer pH 6.8 or simulated intestinal fluid without enzymes 2.Buffer pH 4.5 3.0.1 M HCl or buffer pH 1.2 or simulated gastric fluid without enzymes Volume of media900 ml or less Temperature37°C ± 0.5°C Sampling points10, 15, 20, 30, 45, (60, 120) min. (typical) Units (individual)12 for “official” studies

10. 10 TG Dekker – WHO, Malaysia Feb 2005 Typical time points Immediate release tablets (capsules) Rationale: 1.Condition 1  ≥ 85% dissolution of both products within 15 minutes  15 minute time point thus essential 2.Condition 2, for calculation of f 2  a minimum of 3 points are required  Only one measurement should be considered after 85 % dissolution (both tablets)  20 minute time point thus first possible one (if 15 minute fails 1 st condition) PointTime 110 215 320 430 545

11. 11 TG Dekker – WHO, Malaysia Feb 2005 Comparative dissolution testing Comparison of products When are dissolution properties of two products (batches) regarded similar?  The profiles should be similar  in all three media Statements of instability or insolubility are not acceptable, but should be demonstrated / justified

12. 12 TG Dekker – WHO, Malaysia Feb 2005 Example 1 Determination of similarity of profiles Example 1-B % API dissolved Time (min) Tablet D (Ref) Tablet E (Test) 105557 157278 208591 3097100 45102100 60103101 f 2 required?Yes f 2 (n = 3 ?) 64 (similar) Example 1-A % API dissolved Time (min) Tablet A (Ref) Tablet B (Test) 108794 159699 2099 3010099 4510199 6010199 f 2 required?No, ≥ 85% in 15 min f 2 (n = N/A ?) profiles similar

13. 13 TG Dekker – WHO, Malaysia Feb 2005 Example 1 Determination of similarity of profiles (cont.) Example 1-D % API dissolved Time (min) Tablet A (Ref) Tablet Y (Test) 108755 159672 209985 3010097 45101102 60101103 f 2 required?Yes f 2 (n = 3 ?) 31 (not similar) Example 1-C % API dissolved Time (min) Tablet X (Ref) Tablet Y (Test) 102934 153841 204750 306364 458079 609591 f 2 required?Yes f 2 (n = 6 ?) 74 (similar)

14. 14 TG Dekker – WHO, Malaysia Feb 2005 Example 2 Ciprofloxacin: two batches of same product Apparatuspaddle at 50 rpm Medium 1: simulated gastric fluid without pepsin (SGF) (900 ml) Medium 2: acetate buffer pH 4.5 (900 ml) Medium 3: phosphate buffer pH 6.8 (900 ml) Temp.:37°C ± 0.5°C (start, middle, end) Units:Twelve tablets per medium, each batch Sampling:Manual, through in-line filter (0.45 μm PVDF unit) at 10, 15, 20, 30 and 45 minutes Analysis:HPLC analysis for ciprofloxacin ProductManufacturerBatch NrExpiry dateStatus Cipro 500ABC Ltdxxx06/2007Test Cipro 500ABC Ltdzzz07/2007Reference

15. 15 TG Dekker – WHO, Malaysia Feb 2005 Example 2 Ciprofloxacin: two batches (cont.) Conclusion: The profiles in all three media can be regarded similar / not similar, since ………… Medium►SGF, pH 1.16Buffer pH 4.5Buffer pH 6.8 % dissolved Time (min)b/n xxxb/n zzzb/n xxxb/n zzzb/n xxxb/n zzz 10838093962831 15959297993436 209997991003839 30102101100 3940 45102 1013941 similarity ? n = 5 ? ≥ 85% in 15 min. f 2 = 83 (≥ 50)

16. 16 TG Dekker – WHO, Malaysia Feb 2005 Example 2 Ciprofloxacin: two batches (cont.) SGF without pepsin, pH 1.16Acetate buffer pH6.8

17. 17 TG Dekker – WHO, Malaysia Feb 2005 Example 2 Ciprofloxacin: two batches (cont.) Phosphate buffer pH 6.8

18. 18 TG Dekker – WHO, Malaysia Feb 2005 Questions: 1.What dissolution level should ciprofloxacin 250 mg tablets be able to reach in pH 6.8 medium? 2.Should a change in particle size affect the dissolution rate? X. Yu et al. Pharm. Research, 11, 522-527 (1994) Ciprofloxacin (cont.) Solubility is pH dependent:  “Highly soluble” at pH < 6 100% dissolution obtained in pH 4.5 and pH 1.16  At pH 6.8 and 40°C the solubility is about 0.2 mg/ml Explains 40% dissolution for 500 mg dose !! 40°C ▼

19. 19 TG Dekker – WHO, Malaysia Feb 2005 Example 3 Lamivudine 150 mg & zidovudine 300 mg tablets Source, WHO publication:  Ongoing Monitoring of Antiretroviral Products as Part of WHO’s Prequalification Project. Journal of Generic Medicines (accepted for publication, January 2006 edition)  Samples from PQ project or bought/requested  Apparatus:paddle at 75 rpm  Medium:900 ml 0.1 M hydrochloric acid, 37°C  Sample times:5, 10, 15, 20, 30 and 45 minutes  Analysis:HPLC  Data presented for individual APIs in next tables

20. 20 TG Dekker – WHO, Malaysia Feb 2005 Example 3 Lamivudine 150 mg & zidovudine 300 mg tablets (2) Time (min) % Lamivudine of label claim dissolved Combivir®Gen-1Gen-2Gen-3Gen-4 58525926545 109646968581 159765989592 20978098 95 3097 98 96 4597 98 97 ≥ 85 in 15 min ? ✔ Reference no ✔✔✔ f2f2 21

21. TG Dekker – WHO, Malaysia Feb 2005 Example 3 Lamivudine 150 mg & zidovudine 300 mg tablets (3) Time (min) % Zidovudine of label claim dissolved Combivir®Gen-1Gen-2Gen-3Gen-4 58522746845 109744908883 159864979695 2098819910098 309810010199 4599100 99100 ≥ 85 in 15 min ? ✔ Reference no ✔✔✔ f2f2 20

22. 22 TG Dekker – WHO, Malaysia Feb 2005 Example 3 Lamivudine 150 mg & zidovudine 300 mg tablets (4)  Conclusion (considering only 0.1 M HCl as medium) 1.3 products show profile similarity with Combivir® (≥ 85% in 15 minutes) 2.The profiles of Combivir® and Gen-1 are not similar The products may still show bio-equivalency  The dissolution profiles of the APIs in a particular product are similar (true for all 5 products)  Examples: see profiles of Combivir® and Gen-1

23. 23 TG Dekker – WHO, Malaysia Feb 2005 Example 3 Lamivudine 150 mg & zidovudine 300 mg tablets (5) Combivir ® dissolution profileGen-1 dissolution profile 0.1 M hydrochloric acid Note the similarity of the API profiles of each product APIs highly soluble = dissolution controlled by disintegration time Is particle size of APIs expected to be critical ?

24. 24 TG Dekker – WHO, Malaysia Feb 2005 Example 3 Clarithromycin tablets – Proportional formulations  2 strengths prepared from same granulate  f 2 = 31  Profiles not similar !  Solubility of the API in buffer pH 6.8 “low” according to BCS  Do you expect that particle size or polymorphism may have effect on the profiles?

25. 25 TG Dekker – WHO, Malaysia Feb 2005 Effect of Particle Size on Dissolution of Nevirapine Tablets (Source: Ranbaxy) http://www.who.int/medicines/organization/par/FDC/VKAroraWHOGenevaDec.ppt 1 Viramune 2 Nevipan 90% < 31 3 Nevipan 90% < 81 f 2 : 1 vs 2 = 72 ✔ f 2 : 1 vs 3 = 31 X f 2 : 2 vs 3 = 34 X 1 2 3

26. 26 TG Dekker – WHO, Malaysia Feb 2005 Applications 1.For selection of the formulation in the development phase  By comparison of the dissolution profiles of innovator product with those of formulations  Hint: start with comparator product to see: Immediate release? Rapidly dissolving? Very rapidly dissolving? Disintegration testing can aid in the early phases  This should be a basic strategy in R&D to maximize the chances of bioequivalence

27. 27 TG Dekker – WHO, Malaysia Feb 2005 Applications (cont.) 2.It is a requirement of the prequalification programme to submit comparative dissolution data for the bio-batch and innovator batch  Same batches as used in bioequivalence study !  Submit report with data, profile comparison & discussion (see report requirements)  This report form part of pharmaceutical development report Inclusion of the same report in the bioequivalence study report is recommended

28. 28 TG Dekker – WHO, Malaysia Feb 2005 Applications (cont.) 3.Demonstration of in vivo bioequivalence of one or more of the lower strength(s) of an FPP may be waived based on 1.an acceptable in vivo BE study of the highest strength against the comparator product 2.demonstration of similarity of dissolution profiles, 3.if the lower strength is proportionally similar in formula to the higher strength (bio-batch) and 4.if all pharmacokinetic requirements are met Consult the bio-guideline, also for reverse situation

29. 29 TG Dekker – WHO, Malaysia Feb 2005 Applications (cont.) 4.Comparison of the release properties of pivotal batches  To demonstrate in vitro similarity of such batches This is considered essential for retention of efficacy and safety Note that bioequivalence studies are done normally only once on a bio-batch during development It must be demonstrated that the product retains the dissolution characteristics up to production scale  The studies should be submitted in dossier as part of the FPP development report

30. 30 TG Dekker – WHO, Malaysia Feb 2005 Applications (cont.) 5.Selection of the dissolution specifications for product release & stability purposes 1.Conditions and acceptance criteria to be set 2.The dissolution profiles of the bio-batch should be used for this purpose 3.A dissolution specification should be able to detect inadequate release properties of the commercial batches A “generous” dissolution limit has no quality selectivity 4.Example: Combivir ® (from limited data in Example 3) 80% (Q) within 20 (15?) minutes for both APIs under conditions described in Example 3

31. 31 TG Dekker – WHO, Malaysia Feb 2005 Applications (cont.) 6.Post-approval amendment application  A requirement of a particular change may be to demonstrate that the profiles of the amendment batch and the current batch are similar Consult guideline on variations

32. 32 TG Dekker – WHO, Malaysia Feb 2005 Reporting Comparative dissolution data Full report, including 1.Purpose of study 2.Products / batches information Batch number, manufacturing/expiry date, packaging, etc. CoA & size for “own” batches (and BMR for bio-studies report) 3.Dissolution conditions and method 4.Analytical method or reference to part of dossier 5.Results (% API dissolved) Tabulated Graphically Similarity determination / calculation 6.Conclusion

33. 33 TG Dekker – WHO, Malaysia Feb 2005 Guidelines WHO Prequalification 1.Supplement 1 [for use from July 2005 (CPH25)] to: Guideline on Submission of Documentation for Prequalification of Multi-source (Generic) Finished Pharmaceutical Products (FPPs) Used in the Treatment of HIV/AIDS, Malaria and Tuberculosis Dissolution testing Others  Guidance for Industry. Waiver of In-Vivo Bioavailability and Bioequivalence Studies for Immediate-Release Solid Oral Dosage Forms Based on a Biopharmaceutics Classification System. U.S. Department of Health and Human Services, Food and Drug Administration, Center for Drug Evaluation and Research (CDER), August 2000.  CPMP Note for Guidance on the Investigation of Bioavailability and Bioequivalence. The European Agency for the Evaluation of Medicinal Products CPMP/EWP/QWP/1401/98, July 2001

34. 34 TG Dekker – WHO, Malaysia Feb 2005 Some conclusions  Comparative dissolution  should form an essential part of R&D of solid oral dosage forms (including suspensions),  supports bio-studies,  is required for comparison of pharmaceutical release properties of pivotal batches,  is used to set dissolution specifications, and  assists in post-approval changes  It is thus important  to conduct the studies under controlled conditions in the 3 media, all as required by the guidelines,  to take samples for analysis at meaningful intervals and  to be able to determine similarity of profiles