Formulation of venlafaxine for once daily administration using polymeric material hybrids.

ABSTRACT

OBJECTIVE: Controlled release venlafaxine for once daily administration. METHODS: Drug resin complexation followed by polymer encapsulation. A 4(1).2(1) factorial design was used to study the effect of polymer type and core coat ratio on the release profile and kinetics. Polymer combinations were tried for optimisation adapting the desIMNCility function. The optimised formula was tested in rabbits against commercial extended release capsules. RESULTS: Poly-epsilon-caprolactone, poly(d, l-lactide-co-glycolide) ester and poly(d, l-lactide) ester polymers were more efficient in lowering the release rate and the initial burst release than Eudragit(®)RS100. Encapsulation at 11 ratio ensured complete coats and drug release sustainment. Formula prepared using 5050 PLA/Eudragit at 11 ratio sustained the drug release up to 24 h with low burst release. This formula had higher venlafaxine absorption in rabbits compared to the commercial capsules. CONCLUSIONS: The optimised formula is superior to the available once-daily trials regarding enhanced bioavailability, dosage form versatility and ease of scaling up.