Physical chemistry is the basis of rational pharmaceutical formulation and processing, and is fundamental to understanding the complexities of drug delivery and drug absorption. This textbook presents the physiochemical principles useful to the modern pharmaceutical scientist and pharmacist. microdissociation constants, nominal mesh aperture, percentage ionisation, other disperse systems, solubilising capacity, tertiary butyl acetate, adjusting substance, unionised species, other biopharmaceuticals, colloid stability theory, unionised form, space doses, solubilising agents, internal droplets, controlled flocculation, nonionic micelles, drug stability, nominal aperture, polyoxyethylene glycols, sodium cromoglicate, micellar properties, codeine sulfate, drug ion, micellar size, rectal cavity.