Irrespective of the analytical method used, the first step in identifying potential counterfeit drugs is the careful visual inspection of the product, and its packaging and labelling. A comparison with the authentic drug product is always preferred. Differences in labelling, packaging and the physical appearance of dosage form, e.g. shape, colour, etc., indicate a potential counterfeit (8,9,24).
Even in the absence of knowledge of the physical characteristics of the authentic drug, a visual inspection may indicate that there has been tampering, that there is non-uniform colouration of the drug product under investigation, etc. Again such observations signal the possibility of a counterfeit.
Legitimate drug manufacturers should be encouraged to collaborate with national DRAs and with WHO by providing information and materials on the physical attributes of their products; this would be also be to their own benefit.