(1997; 248 pages) [French]
7. Sampling of pharmaceutical dosage forms for acceptance of consignments
The quality of consignments of finished pharmaceutical products frequently needs to be verified at the time of their importation or purchase. The necessary sampling should be performed in accordance both with an appropriate method and with regard to the presumed homogeneity or nonhomogeneity and uniformity or nonuniformity of the consignments. Thus, a consignment of a product from a single manufacturer labelled with a single batch number is assumed to be homogeneous. This assumption is further strengthened in the case of imported products provided with a batch certificate issued in the country of origin in accordance with the WHO Certification Scheme on the Quality of Pharmaceutical Products Moving in International Commerce.1
1WHO Expert Committee on Specifications for Pharmaceutical Preparations. Thirty-first Report. Geneva, World Health Organization, 1990 (WHO Technical Report Series, No. 790), Annex 5.
If these conditions apply and if the size of the batch is reasonable, a single sample for the intended analyses and a single retention sample will suffice. The size of the samples will be determined by the requirements of the analytical procedure according to which the product will be tested. Tests of unit dosage forms for uniformity of weight, volume or content can require a considerable number of units as can tests for sterility. Depending upon the type of the material, the size of the consignment, and the way in which the material is packaged, a sampling unit may be regarded as a box of vials or a box of jars of tablets rather than one of the individual vials or jars. The required number of unit dosage forms is then withdrawn from any individual container in the selected box.
If the consignment consists of one very large batch, or if little experience has been obtained with the product to be sampled, it may be prudent to carry out two independent analyses. Two independent final samples must then be taken from different sampling units. Conversely, when a consignment of moderate size is composed of two or three batches from the same manufacturer, a single sample may suffice, provided that favourable experience has previously been gained with the product and that there is evidence from the expiry date or other information that the batches were produced at approximately the same time.
Pharmaceutical forms supplied in bulk may also need to be examined. These include liquids and semi-solid materials, powdered solids or granulates transported in large containers and intended either for further processing or for direct packaging into final market containers, and unit dosage forms (tablets, capsules) supplied in bulk intended for repackaging into smaller containers.
Unless there is evidence to the contrary, products of this kind labelled with the name of the manufacturer and a single batch number may be assumed to be uniform if they have been produced in accordance with good manufacturing practice and are provided with a certificate issued in the country of origin according to the WHO Certification Scheme. In these circumstances the collection of a single sample sufficient for the intended analyses is adequate.