ABSTRACT
Stability of drug substances in dosage forms is affected not only by their chemistry. but also by their environment. Compatibility studies are generally carried out with new drug substances in combination with common tablet or capsule ingredients to ascertain that the excipients chosen are not detrimental to the integrity of the drug (or of as little damage as possible). When such programs are carried out. it is conventional (Carstensen et aI., 1964) to study combinations both in the absence and the presence of water. This is because, of all the types of substances one encounters in tablet and capsule formulations, in general, the most detrimental is lmter.
