THE COMBINED INCLUSION COMPLEXATION OF ACETONE AND FLUNITRAZEPAM WITH DIMETHYL -CYCLODEXTRIN

Document Type : Original Article

Author

Department of Industrial Pharmacy, Faculty of Pharmacy, Assiut University, Assiut, Egypt

Abstract

Upon recrystallization from acetone, dimethyl  b-cyclodextrin (DM-b -CyD) has shown physicochemical properties changes which were investigated by X-ray diffractometry, differential scanning calorimetry (DSC) and infrared (lR) spectroscopy. X-Ray diffraction analysis showed new crystalline diffraction pattern different from that of intact DM-b-CyD. An endothermic peak was recorded on the DSC thermogram of the recrystallized sample which was attributed to the release of acetone molecules included into DM-b-CyD cavities. Furthermore, the IR spectra of the recrystallized sample showed carbonyl stretching band at 1725 cm-1, although DM-b -CyD has no carbonyl group, which proved the presence of included acetone molecules into DM-b -CyD cavities. The molar ratio of the included acetone molecules into DM-b -CyD molecules was determined by thermogravimetric analysis (TGA) and was found to be 0.73. In addition, when flunitrazepam and DM-b -CyD were recrystallized  from acetone, it was found that flunitrazepam forms crystalline inclusion complex with DM-b -CyD in 1:3 molar ratio showing the same X-ray diffraction pattern of recrystallized DM-b -CyD alone from acetone. This means that the inclusion of acetone molecules into DM-b -CyD took place in addition to the formation of inclusion complex of flunitrazepam with DM-b -CyD.