The Biological Assay of Drugs in India

of variations in the soil, the season, the gathering time, etc. These variations are undesirable from a therapeutic standpoint, especially where they occur in potent drugs. It is essential, therefore, that before these agents are used for medicinal purposes, a certain amount of purity and freedom from admixture with other substances should be strictly ensured. In the case of non-vegetable products also, standardisation is essential to ensure uniformity of action. Standards of purity and quantity of active constituents have, for this reason, been laid down for all kinds of drugs and chemicals intended for human consumption. Chemical methods of assay have been developed, and the finished products have to be adjusted in accordance with the results of such assays. All medicinal agents, however, cannot be standardised by direct chemical means. Standardisation by biological methods, which is a much more difficult problem, is required for many of the important drugs in use. 1. The first group of these agents consists of medicaments which are conveniently described as ' biological products', and includes such substances as sera, vaccines, toxins, antitoxins, phages, etc. These products are liable to bacterial contamination in the process of manufacture, and they cannot safely be sterilised by heat or by chemical agencies without their efficiency being impaired. They are generally given by hypodermic, intramuscular, intravenous or intrathecal injection. Uniformity in their purity, potency and authenticity is, therefore, a matter of vital importance. 2. The second group consists of synthetic chemicals and organo-metallic compounds with