Characterisation of drug-fatty acid composites and their use in drug delivery systems

Abstract

Fatty acids are considered to be useful as carrier materials in the formulation of drug delivery systems. Literature on fatty acid systems, in particular, stearic acid, was reviewed, though in general, research in this area was relatively limited. Of the delivery devices described, little was reported on the mechanism of release from these systems. A range of drug-fatty acid composites were prepared for dissolution studies. Benzoic acid was used in these systems, as it is a well characterised compound, that has often been used as a model drug. Fatty acid type, drug type, and particle size of the components were shown to significantly affect drug release. The effect on drug release, of drug loading, as well as the inclusion of a soluble excipient, was also investigated. Release was typically in agreement with the Higiwhi model, which describes release from an inert matrix. However, in some systems, the initial phase of drug release deviated from diffusion kinetics. Stearic acid microspheres exhibited release, preceded by a burst phase.