This manual has been designed to be used in conjunction with two earlier World Health Organization (WHO) publications, Basic tests for pharmaceutical substances1 and Basic tests for pharmaceutical dosage forms.2 Most of the pharmaceutical substances and dosage forms covered are included in the WHO Model List of Essential Drugs.3 The present volume describes procedures for testing a further 23 pharmaceutical substances and 58 pharmaceutical dosage forms and also for testing four medicinal plant materials (sections 3-5).
1Basic tests for pharmaceutical substances, Geneva, World Health Organization, 1986.
2Basic tests for pharmaceutical dosage forms. Geneva, World Health Organization, 1991.
3The use of essential drugs. Seventh report of the WHO Expert Committee. Geneva, World Health Organization, 1997 (WHO Technical Report Series, No. 867).
These basic tests represent one of the many elements of quality assurance in the pharmaceutical supply system. They have been devised with the following objectives:
(a) to provide a simple and readily applicable method for verifying the identity of a substance, using a limited range of easily available reagents, when the labelling and physical attributes give rise to doubt;
(b) to provide a practicable means of confirming the identity of a substance when a fully equipped laboratory is not available;
(c) to indicate whether gross degradation has occurred in certain substances that are known to decompose readily under adverse conditions.
Basic tests are not, in any circumstances, intended to replace the requirements of The International Pharmacopoeia4 or other pharmacopoeial monographs. These give an assurance of quality whereas basic tests merely confirm identity.
4The International Pharmacopoeia, 3rd ed. Geneva, World Health Organization. Volume 1: General methods of analysis, 1979. Volume 2: Quality specifications, 1981. Volume 3: Quality specifications, 1988. Volume 4: Tests, methods, and general requirements. Quality specifications for pharmaceutical substances, excipients, and dosage forms, 1994.
In 1994, the WHO Expert Committee on Specifications for Pharmaceutical Preparations5 agreed that the scope of these tests should be extended to include additional information and references to other simple test methodologies.
5WHO Expert Committee on Specifications for Pharmaceutical Preparations. Thirty-fourth Report. Geneva, World Health Organization, 1996 (WHO Technical Report Series, No. 863).
The usefulness of simplified analytical technology and supporting elements, such as thin-layer chromatography (TLC) kits, reference tablets and associated training materials, was fully endorsed by the Committee. They are considered to be valuable tools for primary screening and could play an important part in identifying counterfeit and spurious products. Several collections of simplified tests are therefore reviewed in this manual (see section 2).
Degradation during storage and transportation is of particular importance in tropical countries. Indeed, an expiry date determined for a temperate climate may be inappropriate in a tropical region even when high standards of packaging are met. For this reason, particular importance is accorded to visual inspection of dosage forms, since this frequently provides a first vital indication of degradation. This also applies in cases where there are reasons to suspect quality defects due to poor manufacture, tampering, or counterfeiting. Visual inspection should precede any testing. Inspection procedures are outlined in Basic tests for pharmaceutical dosage forms.
Basic tests need not be carried out by fully qualified pharmacists or chemists, but they should be performed by persons with some understanding of analytical chemistry such as that acquired in courses for pharmaceutical assistants.
The facilities needed for carrying out basic tests, the equipment required and methods for the determination of melting characteristics are described in detail in the two earlier manuals of basic tests. Reagents additional to the ones described in those two manuals are listed in section 6.
Several tests are described for most preparations. Not all of these need to be applied to any one sample. If, however, there is any reason to suspect that the product is mislabelled or substandard, all tests described should be performed. By their nature, simplified tests cannot be totally reliable. An adverse result, even in one test, should be taken as a warning of potential unsuitability of a drug. In these circumstances, a final conclusion should not be drawn until a full analytical examination has been carried out in a properly equipped quality control laboratory.
For easy reference, section 7 provides a cumulative index of WHO basic tests.
Comments on the tests described are invited and should be addressed to: Quality Assurance, Division of Drug Management and Policies, World Health Organization, 1211 Geneva 27, Switzerland.