Sustained Release from Inert Wax Matrixes III: Effect of Povidone on Tripelennamine Hydrochloride Release

Abstract

The utilization of povidone as a channeling agent in the formulation of a sustained-release tripelennamine hydrochloride core significantly influenced drug release over 10hr. Povidone was incorporated into a mixture of carnauba wax and stearyl alcohol by fusion and subsequent congealing in concentrations of 5, 10, and 20% (w/w); the stearyl alcohol concentration was altered to maintain a constant tripelennamine content. Tablet hardness and weight were also held constant. With the povidone-free formulation as a control, the addition of 5% of the channeling agent increased the release by 37% over 8 hr; at the 20% level, the increase was 55%. Between 0.5 and 8 hr, the drug appeared to be released by a zero-order process and a plateau was then approached. Over this interval, the dissolution pattern approached the optimum situation of 10% release/hr with 10–20% povidone. The results obtained from cores made by double compression of the dry-blended ingredients indicated that fusion is essential for channel formation. There was no evidence of complexation between tripelennamine and povidone. A decrease in the release rate was obtained when the polymer was included in the dissolution medium. It appears that channel formation is the mechanism underlying the increase in the drug dissolution rate from cores containing the polymer.