[Modeling the kinetics of theophylline release from a semi-solid matrix: Gelucire]

Controlling release of a trace is an indispensable pharmacological technique. Release of the active substance can be modulated to meet the desired kinetic requirements of the formulation by carefully choosing the excipient and controlling the solubility of the tracer. We studied the preformulation of a semi-solid matrix, Gelucire, to examine the kinetic properties of theophylline release. Several models were analyzed. The results show that the formulation must be specific for the semi-solid matrix used.