WHO Expert Committee on Specifications for Pharmaceutical Preparations - WHO Technical Report Series, No. 863 - Thirty-fourth Report: Annex 9 - Multisource (generic) pharmaceutical products: guidelines on registration requirements to establish interchangeability: Part Two. Equivalence studies needed for marketing authorization: 9. When equivalence studies are necessary and types of studies required: In vivo studies

WHO Expert Committee on Specifications for Pharmaceutical Preparations - WHO Technical Report Series, No. 863 - Thirty-fourth Report
(1996; 200 pages)

Table of Contents

1. Introduction
2. The international pharmacopoeia and related activities
	2.1. Quality specifications for drug substances and dosage forms
	2.2. Test methodology
	2.3. International Nonproprietary Names for pharmaceutical substances
	2.4. International Chemical Reference Substances and International Infrared Spectra
3. Simple test methodology
4. Stability of dosage forms
	4.1. Guidelines for the stability testing of pharmaceutical products containing established drug substances
	4.2. Joint WHO/UNICEF study on the quality of selected drugs at the point of use in developing countries
5. Good manufacturing practices for pharmaceutical products
	5.1. Adoption of additional guidelines
	5.2. Further guidance on good manufacturing practices
6. Legal and administrative aspects of the functioning of national drug regulatory authorities
	6.1. Multisource (generic) pharmaceutical products: guidelines on registration requirements to establish interchangeability
	6.2. The WHO Certification Scheme on the Quality of Pharmaceutical Products Moving in International Commerce
	6.3. Guiding principles for formulating national drug legislation
	6.4. Role of the pharmacist
	6.5. Model legislative provisions to update national legal texts to deal with counterfeit drugs
	6.6. Additional guidance
	6.7. Training activities
7. Quality assurance in the supply system
	7.1. Guidelines on import procedures for pharmaceutical products
	7.2. Guidelines for inspection of drug distribution channels
8. Terminology
Acknowledgements
References
Annex 1 - Guidelines for the graphic representation of chemical formulae
	1. Introduction
	2. Acyclic structures
	3. Cyclic structures
	4. Ionic structures
	5. Isotopically modified compounds
	6. Coordination compounds
	7. Stereochemistry
	8. Carbohydrates
	9. Steroids
	10. Terpenoids
	11. Prostanoids
	12. Alkaloids
	13. Antibiotics
	14. Polypeptides
	15. Polymers
	Acknowledgements
	References
Annex 2 - List of available International Chemical Reference Substances¹
Annex 3 - List of available International Infrared Reference Spectra
Annex 4 - General recommendations for the preparation and use of infrared spectra in pharmaceutical analysis
	1. Introduction
	2. Apparatus
	3. Method of verification of frequency scale and resolution
	4. Environment
	5. Use of solvents
	6. Preparation of the substance to be examined
	7. Identification by reference substance
	8. Identification by reference spectrum
	9. Reflectance techniques
Annex 5 - Guidelines for stability testing of pharmaceutical products containing well established drug substances in conventional dosage forms
	General
	Definitions
	1. Stability testing
	3. Design of stability studies
	4. Analytical methods
	5. Stability report
	6. Shelf-life and recommended storage conditions
	References
	Official, international and national guidelines
	Appendix 1 - Survey on the stability of pharmaceutical preparations included in the WHO Model List of Essential Drugs: answer sheet
	Appendix 2 - Stability testing: summary sheet
Annex 6 - Good manufacturing practices: guidelines on the validation of manufacturing processes
	Introduction
	Glossary
	General
	1. Types of process validation
	2. Prerequisites for process validation
	3. Approaches
	4. Organization
	5. Scope of a process validation programme
	6. Validation protocol and report
	References
	Bibliography
Annex 7 - Good manufacturing practices: supplementary guidelines for the manufacture of investigational pharmaceutical products for clinical trials in humans
	1. Introductory note
	2. General considerations
	3. Glossary
	4. Quality assurance
	5. Validation¹
	6. Complaints
	7. Recalls
	8. Personnel
	9. Premises and equipment
	10. Materials
	11. Documentation
	12. Production
	13. Quality control
	14. Shipping, returns, and destruction
	References
Annex 8 - Good manufacturing practices: supplementary guidelines for the manufacture of herbal medicinal products¹
	1. Glossary
	2. General
	3. Premises
	4. Documentation
	5. Quality control
	6. Stability tests
	References
Annex 9 - Multisource (generic) pharmaceutical products: guidelines on registration requirements to establish interchangeability
	Introduction
	Glossary
	Part One. Regulatory assessment of interchangeable multisource pharmaceutical products
		1. General considerations
		2. Multisource products and interchangeability
		3. Technical data for regulatory assessment
		4. Product information and promotion
		5. Collaboration between drug regulatory authorities
		6. Exchange of evaluation reports
	Part Two. Equivalence studies needed for marketing authorization
		7. Documentation of equivalence for marketing authorization
		8. When equivalence studies are not necessary
		9. When equivalence studies are necessary and types of studies required
			In vivo studies
			In vitro studies
	Part Three. Tests for equivalence
		10. Bioequivalence studies in humans
			Subjects
			Design
			Studies of metabolites
			Measurement of individual isomers for chiral drug substance products
			Validation of analytical procedures
			Reserve samples
			Statistical analysis and acceptance criteria
			Reporting of results
		11. Pharmacodynamic studies
		12. Clinical trials
		13. In vitro dissolution
	Part Four. In vitro dissolution tests in product development and quality control
	Part Five. Clinically important variations in bioavailability leading to non-approval of the product
	Part Six. Studies needed to support new post-marketing manufacturing conditions
	Part Seven. Choice of reference product
	Authors
	References
	Appendix 1 - Examples of national requirements for in vivo equivalence studies for drugs included in the WHO Model List of Essential Drugs (Canada, Germany and the USA, December 1994)
	Appendix 2 - Explanation of symbols used in the design of bioequivalence studies in humans, and commonly used pharmacokinetic abbreviations
	Appendix 3 - Technical aspects of bioequivalence statistics
Annex 10 - Guidelines for implementation of the WHO Certification Scheme on the Quality of Pharmaceutical Products Moving in International Commerce
	1. Provisions and objectives
	2. Eligibility for participation
	3. Requesting a certificate
	4. Issuing a certificate
	5. Notifying and investigating a quality defect
	References
	Appendix 1 - Model Certificate of a Pharmaceutical Product
	Appendix 2 - Model Statement of Licensing Status of Pharmaceutical Product(s)
	Appendix 3 - Model Batch Certificate of a Pharmaceutical Product
	Appendix 4 - Glossary and index
Annex 11 - Guidelines for the assessment of herbal medicines^1,2
	Introduction
	Assessment of quality
	Assessment of safety
	Assessment of efficacy
	Intended use
	Utilization of these guidelines
Annex 12 - Guidelines on import procedures for pharmaceutical products
	1. Introductory notes
	2. Objectives and scope
	3. Legal responsibilities
	4. Legal basis of control
	5. Required documentation
	6. Implementation of controls
	7. Procedures applicable to pharmaceutical starting materials
	8. Storage facilities
	9. Training requirements
	References
	Glossary
	Appendix - Special import controls for narcotic drugs and psychotropic substances¹
Back Cover

In vivo studies

For certain drugs and dosage forms, in vivo documentation of equivalence, through either a bioequivalence study, a comparative clinical pharmacodynamic study, or a comparative clinical trial, is regarded as especially important. Examples include:

(a) oral immediate-release pharmaceutical products with systemic action when one or more of the following criteria apply:

(i) indicated for serious conditions requiring assured therapeutic response;

(ii) narrow therapeutic window/safety margin; steep dose-response curve;

(iii) pharmacokinetics complicated by variable or incomplete absorption or absorption window, non-linear pharmacokinetics, presystemic elimination/high first-pass metabolism >70%;

(iv) unfavourable physicochemical properties, e.g. low solubility, instability, metastable modifications, poor permeability;

(v) documented evidence for bioavailability problems related either to the drug itself or to drugs of similar chemical structure or formulation;

(vi) high ratio of excipients to active ingredients;

(b) non-oral and non-parenteral pharmaceutical products designed to act by systemic absorption (e.g. transdermal patches, suppositories);

(c) sustained-release and other types of modified-release pharmaceutical products designed to act by systemic absorption;

(d) fixed combination products (4) with systemic action;

(e) non-solution pharmaceutical products for non-systemic use (oral, nasal, ocular, dermal, rectal, vaginal, etc.) and intended to act without systemic absorption. The concept of bioequivalence is then not applicable, and comparative clinical or pharmacodynamic studies are required to prove equivalence. This does not, however, exclude the potential need for drug concentration measurements in order to assess unintended partial absorption.

For the first four types of pharmaceutical products, plasma concentration measurements over time (bioequivalence) are normally sufficient proof of efficacy and safety. For the last type, as already pointed out, the bioequivalence concept is not applicable, and comparative clinical or pharmacodynamic studies are required to prove equivalence.