Diclofenac sodium as eye drop solution is considered as the most effective non- steroidal anti-inflammatory agent commonly used in the management and prevention of ocular inflammation.
This research included the study of different factors that may affect on diclofenac sodium in its aqueous solution in order to develop and optimize best delivery of the drug to the eye (as eye drops) with maximum local concentration and minimum systemic absorption and toxicity.
The results showed that the use of hydroxypropyl beta cyclodextrin HP-ß-CD as a solubilizing agent gave more stable formula for diclofenac sodium solution, where the shelf life was about 1.92 years.
The results also indicated that the use of disodium edetate as a sequestering agent gave more stable formula, and diclofenac sodium undergoes hydrolysis at low and high pH with optimum stability at pH 7, which is the most suitable pH for the formulation of this ophthalmic solution.
Also, it was found that the type of buffer slightly affects rate of hydrolysis of diclofenac sodium and optimum stability was obtained by using phosphate buffer. In addition, the results indicated that the concentration of phosphate and borate buffers had significant effect on the hydrolysis of diclofenac sodium and the rate of hydrolysis increased as the concentration of both buffers increased.
Moreover, the results showed that ionic strength affects the hydrolysis rate of diclofenac sodium and the hydrolysis increased as the ionic strength increased in both borate and phosphate buffer.
The results showed that light had a significant effect on the rate of hydrolysis of the drug and the drug losses 10% of its potency after 9.73 months of light exposure at room temperature.
On the hand, the results showed that the formula had no irritation on the eye of experimental animals, and it passes successfully quality control tests including: drug content, pH, clarity and sterility test, and comply with united state pharmacopoeia for ophthalmic solutions.