ABSTRACT
Drug discovery and development involves a complex process from early discovery of a chemical entity to demonstration of its safety and effectiveness for specific therapeutic indication(s). This chapter deals with pharmaceutical considerations for development of new chemical entities only, which usually require the greatest amount of investigation for safety and clinical evaluation to demonstrate their effectiveness. The development process usually begins with preformulation characterisation of drug substance. Preformulation investigation usually commences with complete analytical characterisation of the drug with regard to chemical purity, including the level and nature of impurities. The ultimate goal in the drug design and development process is to improve or optimise the biological performance of drugs. To summarise, the drug discovery and development process involves a complex interplay of physicochemical, biological, dosage form and route of administration considerations. These considerations have significant impact on the biological performance of drugs by governing transport across biological barriers.
