STABILITY OF PREDNISOLONE IN AN ORGANIC VEHICLE

Prednisolone (0.7042 Gm.) was dissolved in 35 ml. of a vehicle (CMP) composed of 50 percent camphor, 25 percent m‐cresyl acetate, and 25 percent p‐chlorophenol, a mixture used in dentistry as a pulp‐capping agent to reduce sensitivity in dental restorations. This preparation was assayed by the blue tetrazolium reaction and compared with an identically treated sample of USP reference standard prednisolone. The prednisolone–CMP mixture was then incubated at 60° with aliquots collected for assay at intervals of 24 hr., 5 days, 1 week, 2 weeks, and 6 weeks. At the end of 2 weeks of incubation, 99.3 percent of the prednisolone still remained; after 6 weeks' incubation, the prednisolone concentration had dropped to 72.4 percent of the preincubation concentration. Compared to literature values on the thermal stability of aqueous preparations of prednisolone, these results indicate that prednisolone in CMP is quite stable. Copyright © 1968 Wiley‐Liss, Inc., A Wiley Company