Formulation and Evaluation of a Polyherbal Nanoparticle-Loaded In Situ Ophthalmic Gel Containing Camellia sinensis and Ocimum sanctum

The present investigation focuses on the development of a novel ocular drug delivery system incorporating herbal extracts of Camellia sinensis and Ocimum sanctum. The study was designed to overcome the limitations associated with conventional ophthalmic preparations such as poor bioavailability and rapid precorneal elimination. Hydroalcoholic extracts of both plants were prepared and characterized for phytochemical constituents. Polymeric nanoparticles were formulated using chitosan and sodium tripolyphosphate through ionic gelation technique. The prepared nanoparticles were further incorporated into a pH-responsive in situ gel system using Carbopol 934 and HPMC K4M. The nanoparticles exhibited nanoscale size distribution with a positive surface charge and satisfactory drug entrapment efficiency. Drug release studies demonstrated a sustained release profile over 12 hours. The in situ gel formulations were evaluated for clarity, pH, viscosity, gelation behavior, drug content, sterility, and ocular irritation. Among the five formulations, F3 showed optimum characteristics, including suitable viscosity, strong gelation, high drug content, and controlled drug release without causing irritation. The developed system successfully combined nanoparticle technology with in situ gelation, resulting in enhanced ocular residence time and improved drug release behavior. This approach offers a promising strategy for delivering polyherbal therapeutics in ocular disorders.