Hollow fibers as an oral sustained-release delivery system.

Phenylpropanolamine (PPA) bound to ion-exchange resin was encapsulated in hollow fibers made of segmented polyurethane. This system was examined as an oral sustained-release delivery system. The fibers were spun by the phase inversion process and cut into different aspect ratios (length/diameter). The U.S.P. basket dissolution method was used to evaluate the in vitro drug release kinetics and the effect of the aspect ratio on the release. For in vivo evaluation, selected fibers were orally administered to dogs in gelatin capsules. The fiber delivery system provided a sustained-release profile of plasma PPA and a longer terminal half-life when compared to an oral immediate-release formulation.