カルバマゼピン結晶性粉末の吸湿性

抄録

Three anhydrous forms (forms I, II, and III), dihydrate (form IV) and monoacetonate (form V) of carbamazepine were prepared and characterized by elemental analysis, infrared spectrum, X-ray powder diffraction, differential scanning calorimetry (DSC), and differential thermal analysis (DTA). The phase transition of these crystalline forms was investigated. Form I obtained by recrystallization from ethanol and form III obtained by drying form IV at 115°C under reduced pressure in P₂O₅ desicator, were very stable to moisture. Form II is relatively hygroscopic and when it was stored under 100% of relative humidity (R. H.) for 3 d, it was transformed to dihydrate (form IV) by absorbing 2 mol of water. Form IV was stable to moisture, when it was stored under 40-91% of R. H. at 37°C. But when it was stored under less than 32% of R. H. for 2 weeks, it lost 2 mol of water and was transformed to form III. Form V obtained by recrystallization from acetone was monoacetonate, and when it was stored under 100% of R. H. for 2 weeks, it lost acetone, absorbed 2 mol of water, and was transformed to form IV. Thermal analysis was also carried out for these crystalline forms and transition temperature, heat of transition, desolvation temperature, and heat of desolvation were measured by DSC and DTA.