Stability of the powdered dosage form prepared by unsealing the capsules: Water vapor sorption and discoloration of the powdery contents of clorazepate dipotassium capsules

The hygroscopicity of the contents of clorazepate dipotassium (Mendon(R)) c apsules (CM) was investigated by storage at various relative humidities (RH s). The CM adsorbed water vapor significantly at more than 75% RH. At the s ame time, a marked discoloration of CM from white to yellow was also observ ed during storage. On the basis of differential scanning calorimetry (DSC) and Fourier transform (FT) Raman spectroscopy, the discoloration seemed to be due to the change in clorazepate dipotassium to nordiazepam and other su bstances. It was found that, when opening of the Mendon capsule is necessar y to prepare the powdered dosage form, the CM should be stored below 60% RH to avoid the adsorption of water vapor and discoloration.