APPROACHES TO STEREOSPECIFIC PREFORMULATION OF IBUPROFEN

In an effort to formulate the pharmacologically active ibuprofen isomer ((+)-S-ibuprofen) into a solid oral dosage form, preformulation studies were performed on both the racemate and this stereoisomer of ibuprofen. Results of the respective physical pharmacy profiles were compared to predict the pharmaceutical behavior of the S(+) ibuprofen compound. The enantiomer was more soluble than the racemate in aqueous media but exhibited lower intrinsic dissolution rates, as would be expected from the very small specific surface area. This characteristic could be a limiting step in the formulation of the optical isomer although less energy was required for the solution of S(+) ibuprofen. On this crystal, there was ten times more moisture layered at the surface and comparative thermal analysis indicated that for both compounds a loss in crystallinity occured upon grinding. Properties in the solid state of S(+) ibuprofen included higher density and excellent flowability as compared to the racemate.