S Chand Pharmaceutical Biotechnoloy by Dr. K. Adinarayana, Dr. KN Jayaveera & Dr. V. Sreenivasulu

Pharmaceuticals may also be described as "specialty", independent of other classifications, which is an ill-defined class of drugs that might be difficult to administer, require special handling during administration, require patient monitoring during and immediately after administration, have particular regulatory requirements restricting their use, and are generally expensive relative to other drugs.