controlled release polymeric ocular inserts for delivery of acyclovir

The poor bioavailability and therapeutic response exhibited by conventional ophthalmic solutions due to rapid precorneal elimination of drug may be overcome by the use of ocular inserts, which achieve increased bioavailability by controlled release of drug. The purpose of the present research is to fabricate reservoir-type ocular inserts, by sandwiching the hydroxypropyl methylcellulose (HPMC) matrix containing acyclovir (ACV) in between two rate controlling membranes of cellulose acetate phthalate (CAP). ACV is a poorly aqueous soluble drug, and to improve its solubility it was complexed with β-cyclodextrin (BCD) and then incorporated into HPMC matrix. Polyethylene glycol (PEG-400) (10 % w/w) was incorporated as a plasticizer as well as permeation enhancer. Nine inserts (AO-1 to AO-9) with varying ratio of HPMC (drug matrix) and CAP (rate controlling membrane) were developed. The formulations were subjected to physicochemical evaluations, drug content uniformity studies, in vitro and in vivo drug release studies, interaction and stability studies. The in vitro release studies revealed that the formulations with 5% CAP was found to be optimum as rate controlling membrane. Based on the results of in vitro release studies the optimized formulations were selected for in vivo evaluation in rabbits. A high correlation coefficient was found between in vitro/in vivo release rate studies. Also the study confirmed the improved solubility of ACV when complexed with β-cyclodextrin. It can be concluded that the ocular inserts was remained stable and a shelf life of 1.8 years was assigned