Abstract

In ocular delivery, conventional drug administration systems have significant pitfalls, such as low bioavailability, low residence time and rapid precorneal drainage. An in situ gel is a novel drug delivery system with prolonged pharmacological action and simpler production techniques. This investigation aims to formulate and evaluate pH-responsive ophthalmic in situ gel of Ciprofloxacin hydrochloride and Olopatadine hydrochloride. The nine batches of ophthalmic in situ gel were prepared using carbapol-980 as a gelling agent and hydroxypropyl cellulose as a viscosity modifier. The designed formulations were examined for visual appearance, clarity, pH, gelling time, viscosity, drug content, in vitro drug release and stability study. The study's outcome explored that in situ gelling systems were translucent and clear, with a pH ranging from 4±0.26 to 7± 0.27, suitable for ocular application. In gelling time study, F1, F2, and F3 batches required 34-39 min for gel formation and showed approximately a 4-5 times increase in the viscosity after gelation compared to all batches. In drug content analysis F3 batch exhibited the highest amount of drug content, 99.90±0.25 % for Ciprofloxacin hydrochloride and 101.45±0.93 % for Olopatadine hydrochloride; hence this batch was subjected to a drug release study. The kinetic study explored the resulting data best fitted to Korsmeyer-Peppas than zero order, first order, Higuchi models. A stability investigation exhibited no alteration in the formulation at 40°±2° with a relative humidity of 75 %-5 % RH after 3 mo. A compressive finding explored that ophthalmic pH-responsive in situ gel can be a potential approach for treating conjunctivitis.