Formulation and Evaluation of Extended Release Ocular Inserts prepared from Synthetic and Natural Biodegradable -Biocompatible Polymers

Objective of this research was to formulate and evaluate extended release ocular inserts/films of anti-conjunctival drug, Sodium Cromoglycate. Novel natural polymer namely, Pullulan and synthetic polymer namely, Hydroxy Ethyl Cellulose (HEC) were used as biodegradable, biocompatible polymers. Standardized glass mould was used to prepare ocular inserts. The ocular inserts were prepared with constant drug content and 10% concentration of polymer. The aim was to maintain the thickness of ocular insert at not more than 0.40 mm. Ocular inserts were prepared using Pullulan 10% and HEC 10%. Formulated ocular inserts were evaluated for parameters like appearance, thickness, weight variation and uniformity of drug content. For in vitro studies, In-House (IH) vial method was used to determine the rate of dissolution using phosphate buffer saline (pH 7.4). Ocular inserts prepared from both polymers showed differences with respect to physical properties such as appearance, weight and thickness. Films of both the polymers showed differences with respect to physico-chemical properties such as appearance, weight and thickness. The films were smooth, thin, soft and pliable. Appearance of Pullulan 10% films was almost clear to slightly opaque whereas films of HEC 10% were slightly off white in color. The Pullulan 10% films had average thickness of 0.21mm and films of HEC 10% had average thickness of 0.19mm. The average weights of Pullulan 10% films were 10.8 mg whereas average weight of HEC 10% films was found to be 14.8 mg. The drug content of Pullulan 10% film and HEC 10% film was confirming to limits. The in vitro release study was carried out using phosphate buffer saline of pH 7.4. Both the films dissolved completely over a period of time. Pullulan 10% films showed in vitro release for 3 hours whereas HEC 10% films showed in vitro release for 6 hours. However, since the thickness of Pullulan 10% films are well within required specification of less than 0.40 mm, further studies shall be carried out with Pullulan by increasing the concentration and shall then evaluated for thickness and in vitro release studies. We assume that higher concentration of Pullulan films can extend the drug release for few more hours thus yielding promising result.