Solid state stability of ketoprofen in the presence of different excipients

Physical mixtures of ketoprofen (KT) were prepared using different excipien ts, namely, lactose, mannitol, sorbitol, beta-cyclodextrin, polyvinylpyroli done (PVP) K30, polyethyleneglycol (PEG) 20,000 and urea in a ratio of 2:1 (drug/excipient). The prepared samples as well as KT alone were stored at 4 0, 50 and 60 degrees C in sealed glass vials for 12 weeks. The fresh and st ored samples were subjected to physical examination and instrumental analys is including m.p., IR and dissolution rate. KT without additives was found to be physically stable or when mixed with either lactose, mannitol, sorbit ol or beta-cyclodextrin for 12 weeks at 60 degrees C. The m.p, of the drug alone or in presence of these excipients did not change. Also IR showed no change. On the other hand, KT mixtures with PVP K30, PEG 20,000 or urea wer e physically unstable on storage at 40, 50 and 60 degrees C. Their m.p. wer e found to decrease; the IR curves were also changed. All the tested excipi ents enhanced the dissolution of KT from its physical mixtures and could be arranged according to the extent of dissolution as follows: Lactose = Mann itol > beta-cyclodextrin > PVP K30 = Urea > Sorbitol > PEG 20,000.