Active pharmaceutical ingredients

1. Active pharmaceutical ingredients Presented By Rutendo Kuwana Training workshop: Training workshop on regulatory requirements for registration of Artemisinin based combined medicines and assessment of data submitted to regulatory authorities, February 23-27, 2009, Kampala, Uganda.

2. Presentation approach • Discuss aspects of the information that is required for the API for WHO Prequalification • Use examples from literature as well as experience from the WHO PQ Project

3. Some definitions Active Pharmaceutical Ingredient (API) A substance or compound that is intended to be used in the manufacture of a pharmaceutical product as a therapeutically active compound (ingredient)

4. Some definitions (2) Enantiomers cpds with same molecular formula as substance but differ in spatial arrangement of atoms and are non-superimpossable mirror images Polymorphism – occurrence of different crystalline forms of the same substance Degradation product – molecule resulting from chemical change in substance due to e.g. light, temperature, pH, water, reaction with excipient, immediate container/closure

5. Some definitions (3) Impurity – any component of the medicinal product which is not the chemical entity defined as the active substance or an excipient of the product Identified Impurity – an impurity for which structural characterisation has been achieved Unidentified degradation product – an impurity defined only by qualitative properties e.g. Rt

6. Available information on API Applicants should collect and analyse available information of the API in a systematic approach. This approach • Leads to a sound scientific understanding of the API, with respect to properties, stability, specifications, etc. • Assists in API manufacture and DMF compilation • Leads to the appropriate choice of API manufacturer (source) • Assists in dossier compilation • Is important for FPP pharmaceutical development • Leads to reduction of time / cost

7. Literature information on API Standard works / series / books – such as: • (Analytical) Profiles of Drug Substances and Excipients [eds: Florey / Brittain – 31 volumes] • The Merck Index (for structures, properties) • Pharmaceutical Codex (12th edition) (“old” APIs) Journals through search facilities such as • International Pharmaceutical Abstracts, Chemical Abstracts, Analytical Abstracts & internet Pharmacopoeial monographs (current) Analysis of structure & stereochemistry

8. Information from literature and structures • APIs which are organic compounds, have unique chemical structures & stereochemistry • These structures, together with the solid/liquid state conditions, are basically responsible for chemical and physical properties of the APIs

9. Guidelines • 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 [GuideGeneric] • Guidance on Variations to a prequalified Dossier [Variation Guide] • Guideline on Active Substance Master File Procedure [CPMP/QWP/227/02 Rev1] • Guideline on Active Pharmaceutical Ingredient Master File (APIMF) Procedure [Draft] • Guideline on Summary of Requirements for Active Substances in the Quality Part of the Dossier [CPMP/QWP/297/97 Rev 1 corr] • ICH Q3A [R] Impurities Testing Guideline: Impurities in New Drug Substances [CPMP/ICH/2737/99] • ICH Q6A Specifications: Test Procedures and Acceptance Criteria for New Drug Substances and New Drug Products: Chemical Substances [CPMP/ICH/367/96 corr] • ICH Q2A Validation of Analytical Procedures: Definitions and Terminology [CPMP/ICH/381/95] • ICH Q2B Validation of Analytical Procedures: Methodology [CPMP/ICH/281/95]

10. Literature support Literature information used in the dossier should always be accompanied by • Full traceable reference citations • Photocopies of publication or relevant pages

11. Properties of APIs Scenarios: API not described in BP, Ph., JP, Ph.Eur., or USP (non - compendial) • Considered new • (?) information on (adverse) drug reaction • Risk estimation high • Profound information necessary API described in BP, Int.Ph., JP, Ph.Eur.,or USP (compendial) • Considered in use • Information on (adverse) drug reaction (monitored) • Risk estimation based on available data • Information necessary limited to data beyond the monograph • Essential control by the monograph

12. Properties of API(s) • APIs not described in BP, PhInt, PhEur or USP • a) evidence of chemical structure • spectral data • Single crystal X-ray structure (sufficient) or • Spectrometric data (IR, 1H & 13C NMR, MS, etc.): QA certified copies of the spectra and tabulated data with • assignments against structure/interpretation of data (narrative) • b)evidence of chemical structure • Isomerism • Stereochemistry • Discussion of potential isomeric forms

13. Properties of API(s) • Properties relevant/critical for the performance of the API • c) potential polymorphic forms • Influence on physicochemical and physical characteristics (solubility, hardness, compressibility, density, melting point, etc.) Must be controlled • d) particle size distribution • requirement for low solubility drugs (dissolution, bioequivalence) • e) additional characteristics • critical characteristics to be controlled to ensure consistent performance of the API (e.g. hygroscopicity)

14. Properties: non-compendial APIs • Proof of structure/stereochemistry correctness • correlation against API spectral data from peer reviewed literature, preferable innovator publication (in tabulated form!!). Strongly recommended

15. Properties of API(s) • APIs described in BP, PhInt, PhEur or USP • Evidence of chemical structure • control of structure by suitable compendial identification tests • Properties relevant/critical for the performance of the API (not necessarily covered by the monograph) • a) potential polymorphic forms • Influence on physicochemical and physical characteristics (solubility, hardness, compressibility, density, melting point, etc.) Must be controlled • b) particle size distribution • requirement for low solubility drugs (dissolution, bioequivalence) • c) additional characteristics • critical characteristics to be controlled to ensure consistent performance of the API (e.g. hygroscopicity)

16. Properties: Compendial APIs • Physico-chemical and other relevant properties, e.g. • Solubility in water (effect of pH), other solvents such as ether, ethanol, acetone and dichloromethane • pKa, partition coefficient • Existence/absence of polymorphs and pseudo-polymorphs e.g. solvates (with XRPD, DSC, IR) • e.g. Rifampicin polymorphs I and II • Hygroscopicity • Particle size

17. Properties of API(s) • Categories of Antimalarials • APIs described in monographs of major international pharmacopoeias ( 10 years) • Amodiaquine, Chloroquine, Dapsone, Quinine, Mefloquine, Sulfadoxine/Pyrimethamine, Trimethoprim • APIs described in monographs of major international pharmacopoeias (recently) • Arthemether, Artemisinin, Artemotil, Artenimol, Artesunate • APIs not described in monographs of major international pharmacopoeias • Chlorproguanil, Lumefantrine, Naphthoquine, Piperaquine, Pyronaridine

18. Malaria APIs: Table of occurrence

19. Malaria APIs: Table of occurrence (con.) Lumefantrine only malaria API without monograph

20. Properties of Artemisinins 8 9 7 8a 10 11 12a 6 12 5a 5 1 3 4 2 • Artemisinin (C15H22O5) • 7 centers of asymmetry • 27potential isomers • One isomer in biosynthesis • Chemical synthesis • Feasible but uneconomical • Chemical derivatization at C-10 (carbonyl-moiety)converts C-10 into an additional stereoisomeric center: • a- and b-isomers are formed

21. Properties of Artemisinins Manufacturer proposals Diastereomers may differ in their melting point/specific optical rotation

22. Route(s) of synthesis API not described in BP, Int.Ph., JP,Ph.Eur., or USP(non-compendial APIs) • Controls of critical steps and intermediates • Potential impact on the quality of the API and intermediates • Process conditions, test requirements and other relevant parameters to be controlled within predetermined limits • Examples of potentially critical steps • Mixing of multiple components • Phase change and phase separation steps • Steps where control of pH and temperature are critical • Introduction of an essential structural element or major chemical transformation • Introduction/removal of significant impurities to the API • Final purification step • Steps with an impact on solid state properties/homogeneity of the API • API described in BP, Int.Ph., JP, Ph.Eur., or USP(compendial APIs)

23. Route(s) of synthesis (cont.) • Requirements: The synthesis should • lead to the correct structure, stereochemistry and crystal form & size (if relevant) • be well controlled and validated (GMP) • produce an API which meets acceptable standards of quality, including limits of impurities (organic, inorganic, residual solvents)

24. The information required for the synthesis of the API may depend on • Availability of a valid CEP - no synthesis information is then required. CEP must however have all appendices and applicant to submit other info not covered by CEP • Whether the quality of the is API controlled by a monograph in an acknowledged pharmacopoeia? • No official monograph is available for quality control - Detailed information required e.g. Open Part of DMF (from API manufacturer) - Also signed declaration from API manuf that synthesis and purification are as described in the dossier

25. Certification Scheme /EDQMCEP Option • Issued by EDQM for substances described in the Ph. Eur. www.edqm.euunder Certification.Pharm.Substances • Information which can be found on a quality CEP- CEP reference Number,- CEP holder, - Site of manufacture of the API, site of manufacture of declared starting material- Grade (particle size or sterile) (if applicable) - Ph. Eur. monograph according to which the Certification dossier has been evaluated, - Additional impurities and residual solvents not mentioned in the monograph, - Additional methods to those of the monograph as annexes,- If sterile API, Method of sterilization + mention that process and validation have been assessed - Re-test period (if applicable)- Packaging system and storage condition (if re-test period mentioned), - Date of validity of the CEP

26. Certification Scheme /EDQMCEP Option A quality CEP certifies that the quality of the substance can be checked according to the Ph. Eur. by applying the analytical methods described in the specific Ph. Eur. monograph supplemented by those appended to the CEP.

27. Synthesis : non-compendial APIs • A flow diagram of the synthesis process • including structures & stereochemistry of starting materials & intermediates; reagents; catalysts; solvents • A full description of each step / process, including: • Reaction conditions (temp., time, moisture control, etc.) • Quantities of reagents/solvents • Size of production scale • Purification of intermediates • Final API purification method / crystallisation / solvent(s) • Reprocessing (has to be justified, validated) • Process controls • Validation of critical steps, e.g. aseptic processes • Discussion of (possible) process impurities • Organic, residual solvents and catalysts/inorganic

28. API described in BP, PhInt, PhEur or USP • Impurities that are not included in the monograph • Process related impurities • Key intermediates • Residual solvents • Potential organic impurities not covered by the monograph

29. Specifications of raw materials and intermediates used in synthesis Provide specifications for • starting materials and intermediates (if isolated) • reagents, solvents & catalysts Class 1 solvents should not be used (ICH Q3C) • Benzene, Carbon tetrachloride, 1,2-Dichloroethane,1,1-Dichloroethene & 1,1,1-Trichloroethane Provide a declaration on the use/non-use of material of animal or human origin (TSE) • Risk of Transmitting Animal Spongiform Encephalopathy Agents (WHO TRS 908, Annex 1 or EMEA/410/01 Rev.2) To limit impurities in the API (For safety reasons)

30. WHAT IS A STARTING MATERIAL? • Contributes an important structural part of the API • Available in free trade • Compound well defined in chemical literature (name, chemical structure, chemical and physical properties, and impurity profile) • Synthesized by commonly known process

31. RE-DEFINITION OF STARTING MATERIAL MARKS THE START OF THE MANUFACTURING PROCESS DESCRIBED IN AN APPLICATION • Manufacturing steps before are not described • Manufacturing steps before need not be performed in accordance with GMP • Changes in manufacturing steps before need not be reported to WHO EACH BRANCH OF A SYNTHESIS WILL BEGIN WITH ONE OR MORE STARTING MATERIALS

32. API specifications API not described in BP, Int.Ph., JP, Ph.Eur., or USP (non-compendial APIs) API described in BP, Int.Ph., JP, Ph.Eur., or USP (compendial APIs) General note An API has only one set of specifications applicable at release and throughout the re-test period • an FPP may have two sets of specifications – release and shelf-life

33. Specifications: Non-Compendial APIs ICH Q6A (new APIs and products) – for instance: • Requires justification for proposed specifications • Impurities to be characterised and limits set • synthesis and degradation according to ICH Q3A(R) • residual solvents according to ICH Q3C • Analytical methods with validation • Preparation and potency determination/specification of primary and secondary (working) standards, with CoAs Valid CoAs for at least 2 batches

34. Non-compendial APIsTypical set of specifications • Appearance/description • Identification (at least one specific, e.g. IR spectrum) • Moisture content (or LOD: moisture + residual solvents) • Impurities - Related organic substances (synthesis or degradation) • specified • unspecified and • total organic impurities - Inorganic impurities, including catalysts - Residual solvent(s) • Assay • Additional parameters important for specific API • such as particle size, polymorphic form, microbial limits

35. Specs: Compendial APIs • The current monograph always applicable • Additional critical specifications that are not included in monograph e.g. • particle size & polymorphic form • synthesis related impurities resulting from specific process which may be additional to monograph • residual solvents (specific to process) • Valid CoAs for at least 2 batches required CEP normally states tests additional to the monograph • e.g. residual solvents & impurities

36. IMPURITIES • Extraneous contaminant (foreign substances) • Toxic impurities • Concomitant components • Signal impurities

37. Classes of Impurities • Organic • Inorganic • Residual solvents

38. Organic Impurities May arise during manufacturing process and storage • Starting materials • By products • Intermediates • Degradation products • Reagents, ligands and catalysts

39. Inorganic Impurities May be from manufacturing process and are normally known and identified: • Reagents, ligands and catalysts • Heavy metals • Inorganic salts • other materials (e.g. filter aids, charcoal etc.)

40. Solvents Organic or inorganic liquids used during the manufacturing process Toxicity generally known, therefore controls achievable Limits to be based on pharmacopoeial standards or known safety data

41. IMPURITIES • Identified impurity • Unidentified impurity • Specified impurity • Unspecified impurity

42. Impurity Thresholds • Identification thresholdLimit above which, impurities found are to be identified either structurally or by a qualitative parameter e.g. RT in HPLC system • Qualification thresholdLimit above which, impurities found are to be toxicologically qualified • Reporting thresholdLimit from which, impurities should be analytically reported

43. ICH Guidelines for Identification and Qualification of impurities in bulk drugs and FPPs

44. IMPURITY EQUIVALENCE To demonstrate that different sources of the API or routes of synthesis are equivalent, checks on impurities are required to show that • No new impurity is observed in the intermediate above 0.1% • No new impurity is observed in APIabove the qualification threshold • Each existing impurity is within its stated limit • Total impurities are within the stated limit

45. IMPURITY EQUIVALENCE (2) • Each existing residual solvent is within its stated limit • New residual solvents, in either an intermediate or the API, are at or below the levels recommended in the ICH guide

46. IMPURITY EQUIVALENCE (3) Ideally, impurities should be evaluated in isolated intermediates immediately following the process step in which they are produced The impurity search can be extended to the next downstream intermediate and the evaluation process repeated until the final intermediate, even to the API

47. Potential impurities of Artemisinins • Starting material (extracted from herbal sources) • GuideGeneric: • Starting materials from vegetable origin should be fully characterized and a contaminant profile should be established and submitted. • CPMP/QWP/297/97 Rev 1 corr: • In the case of substances isolated form herbal sources, the potential for impurities arising from cultivation and/or preparation (e.g. pesticide residues, fumigants, mycotoxins) should be addressed.

48. Potential impurities of Artemisinins II • Impurities contained in the starting material - Artemisinin • Biosynthetic by-products • Arteannuin B , Artemisitene, Artemisinic acid, • Extraction from fresh leaves with CHCl3 within 1 min > 97% • Localisation in subcuticular space of the glands on the surface of the leaves • Cultivation reagents • Pesticide residues, fumigants, mycotoxins • Solvents from the extraction process • Hexane, benzene, acetonitril, ether, pentane, chloroforme…..(?) diesel, fuel (?) [ICH Q3A (R)]

49. Potential impurities of Artemisinins III • Unreacted starting material • Artemisinin (starting material for derivatives) • Artemisinic acid (starting matrial for dihydroartemisinin) • Dihydroartemisinin (starting material for derivatives) • Unreacted intermediates, by-products • a-Arthemether, a-Artheether • a/b-Dihydroartemisinin • b-Artesunate

50. Potential impurities of Artemisinins III cont. • Reagents, catalysts, residual solvents • Methanol, acetonitril, chloroforme, acetone … • NaBH4, succinic acid/anhydride, triethylamine, dimethylaminopyridine • Degradants • Stability of • ester-derivative (Artesunate) • ether-derivative (Artemether, Arteether) • lactone (Artemisinin) • Stability of artenimol (oxidation) • Susceptibility of endoperoxide bond to reduction • Deoxyartemisinine (loss of active principle!) • Zn / AcOH or FeBr2 / THF