PHYSICO-CHEMICAL STABILITY STUDIES OF DICLOFENAC SODIUM ORAL LIQUID SOLUTION FORMULATED WITH POLY-ETHYLENE GLYCOL, PROPYLENE GLYCOL AND ETHANOL CO-SOLVENTS

The term “stability of a pharmaceutical dosage form” implies the physical and chemical integrity of the active pharmaceutical ingredient (API), the excipients and intactness of the packaging. Excipients plan an important role in determining the quality and performance attributes of pharmaceutical dosage forms. In this study, the effects of a cosolvent system were evaluated for its stability in the formulation of diclofenac sodium oral solution. The co-solvents used for the study were Ethanol, Propylene Glycol and Polyethylene Glycol. Different batches of diclofenac sodium oral liquid solution were formulated with each of three co-solvents separately, in different ratios of water to co-solvent, 3:1, 2:2 and 1:3. The formulations were subjected to test such as Viscosity test, Organoleptic evaluation and pH test at the initial time of formulation, and then 6 weeks after. The viscosity of the different diclofenac formulations ranged from 4.56 to 20.90 at 0 weeks and 6.38 to 25. 90 at 6 weeks. the pH of the formulation ranged from 5.49 to 5.68 for the freshly prepared diclofenac formulations and 4.21 to 5.48 at 6 weeks. The studies show that formulation with PEG was relatively more stable than other co-solvents upon weeks of storage. The stability studies indicated that proper formulation methods with good hygienic practices should be encouraged, in order to avoid degradation over time. The instability of the other formulations points to the susceptibility of these co-solvents to environmental factors such as microbial contamination and humidity in affecting the stability of formulation