ABSTRACT
Particle engineering is a term coined to encompass means of producing particles having a defined morphology, particle size distribution, and composition. In its broadest sense, wet granulation can be considered a means of particle engineering, as it is a way of transforming a diverse set of particle sizes into uniform conglomerates. The rate of dissolution of drug in the amorphous state may exceed that in the crystalline state and in the nano-crystalline state, resulting in an instantaneous solubility which may exceed the equilibrium solubility. Drugs for pulmonary administration can be administered via dry powder inhaler or by inhalation of an aerosolized or vaporized formulation. By varying process parameters and feedstock composition, spray-drying and supercritical fluid processing can be used to prepare particles of various morphologies, densities, and size in a very narrow particle size distribution. A drug which is prone to hydrolysis in aqueous solution may be stabilized by formulating it as an aqueous suspension or nano-suspension.
