Formulation And Stability Evaluation Of Diclofenac Sodium Ophthalmic Gels
An ophthalmic gel of diclofenac sodium, a potent non-steroidal antiinflammatory drug was formulated using polymers of hydroxypropyl methylcellulose, sodium carboxymethylcellulose and methylcellulose. The gels were sterlized and assessed for various parameters like clarity, pH, physical appearance, physical stability, viscosity and uniformity of drug content. Almost 96% of drug was released from the hydroxypropylmethylcellulose formulation within a period of 9 h. Drug release obeys zero order kinetics. In vitro release for different gel formulation after 9 h is expressed in the decreasing order as follows hydroxypropylmethylcellulose gel>methylcellulose gel>sodium carboxymethylcellulose gel. Ocular irritation on score basis study in rabbits reveals that none of the gel formulation showed any redness, inflammation (or) increased tear production when compared with placebo. Diclofenac formulation was found t o b e more stable in hydroxypropylmethylcellulose gel compared to methylcellulose gel and sodium carboxymethylcellulose gel at ambient, refrigerator and incubator temperature. The stability of the gel was evidenced by the degradation rate constant. Formulated ophthalmic gel with hydroxypropylmethylcellulose proves to be a viable alternative to conventional eye drops as it offers longer precorneal residence time and excellent ocular tolerance.