Anti-inflammatory effect of diclofenac-sodium ointment (cream) in topical application

This study was performed to develop a topical ointment of diclofenac-Na which has a potent anti-inflammatory activity by oral administration. At first, research was carried out on the ointment base which influences the external anti-inflammatory effect of the drug. Ointments of diclofenac-Na were prepared with three kinds of bases: lipophilic, emulsion (cream) and gel bases; and their anti-inflammatory effects were compared. The cream was found to have the most potent effect. Therefore, in the next experiment, an optimum concentration of diclofenac-Na in cream was determined comparing the anti-inflammatory effect among the cream preparations containing 0.5, 0.75, 1.0 and 1.5% of the drug. Obvious effects were observed with the cream containing 1.0% and 1.5% of the drug concentration, and there was no significant difference in the anti-inflammatory activities of these two concentrations. Based on these results, the cream preparation containing 1.0% of diclofenac-Na (DF cream) was adopted as the external ointment of the drug. The anti-inflammatory effect of this cream was compared with that of existing anti-inflammatory ointments, i.e., indomethacin gel (IM gel), bufexamac cream (BM cream) and mobilat ointment (ML ointment). DF cream produced obvious inhibition on increased vascular permeability and on acute edema and remarkable suppression of ultraviolet erythema. These activities of DF cream were similar to those of IM gel and more potent than those of BM cream and ML ointment. The inhibitory effect of DF cream on the proliferation of granulation tissue was almost equal to that of ML ointment and more distinguishable than that of IM gel and BM cream. In adjuvant arthritis, DF cream reduced the swelling remarkably in the treated paw and slightly in the untreated paw. The anti-adjuvant activity of DF cream was equal to that of IM gel and more potent than that of BM cream and ML ointment. In pain to pressure stimulation, an analgesic effect was observed in the early stage of DF cream application, and its activity was slightly stronger than that of the other ointments. These results show that DF cream has an obvious anti-inflammatory effect as an external preparation, and the activity is comparable or superior to that of similar existing anti-inflammatory ointments. This cream may be considered as useful in the clinical field as a topical anti-inflammatory preparation.