Preparation and clinical application of 2% diflunisal oral ointment for painful lesions of the oral mucosa

We previously reported the development and clinical efficacy of a 2% aspiri n oral ointment and 2% ethenzamide oral ointment as hospital preparations f or painful lesions of the oral mucosa. This study investigated methods of p reparing a more stable oral ointment with a more effective analgesic action , using diflunisal, another salicylic acid derivative, with an analgesic ef fect stronger than that of aspirin. A two-percent diflunisal oral ointment was prepared similarly to the aspirin ointment using plastibase and CMC-Na as the ointment base. From the results of spreadability measurement, a CMC- Na content of 20% was considered appropriate. The stability of diflunisal i n 2% diflunisal oral ointment stored at 5 degreesC, 20 degreesC and 30 degr eesC, was determined using HPLC, and a high stability of diflunisal at room temperature for more than 100 days was confirmed. We also investigated its antinociceptive effect using the Randall-Selitto paw pressure test in rats , which showed that 2% diflunisal oral ointment was as effective as 2% aspi rin oral ointment. On clinical application of 2 % diflunisal oral ointment to 8 patients with painful oral mucous diseases, it was found to be signifi cantly (p=0.014) more effective than 2% aspirin oral ointment. The results of this study demonstrated that 2% diflunisal oral ointment is a clinically useful analgesic for painful oral lesions.