Crude Drugs

Crude Drugs
The macroscopical characteristics of a crude drug include those features that can be seen by the unaided eye or by the use of a hand lens.
Vegetable drugs are required to be free from insects and other animal matter, and from animal excreta. Not more than traces of foreign organic matter may be present in powdered vegetable drugs. Microbial contamination should be minimal.
In determining the content of active principle, Acid-insoluble ash, Ash, Extractive soluble in ethanol, Loss on drying, Sulphated ash, Water, Water-soluble ash and Water-soluble extractive of vegetable drugs, the calculations are made with reference to the drug that has not been specially dried unless otherwise prescribed in the monograph.
In the assays for alkaloids in crude drugs and their preparations, definite quantities of solvents are specified. The quantities are given as being suitable for typical cases; they may, however, be varied where necessary to overcome the difficulties that may be encountered in special instances, provided that the effect of the prescribed directions is ensured.
When it is found necessary to dry a crude drug before it can be reduced to powder for the purpose of assay, a correction is made for the loss on drying and the alkaloidal content is calculated with reference to the undried drug.