SOLID STATE CHARACTERIZATION OF THE POLYMORPHIC CHANGES IN CANDESARTAN CILEXETIL SOLID DISPERSION WITH POLY ETHYLENE GLYCOL 8000

ABSTRACT:

Aim: The main aim behind this work is to study the effect of thermal methods used for the formulation upon the candesartan cilexetil properties and to evaluate the changes due to temperature

Method: Melt method was followedto study the polymorphic changes in the candesartan cilexetil solid dispersions. In this method different ratios of drug to carrier were selected for the formulation. Initially the carrier was melted in china dish at 80⁰c, when the complete carrier was converted to liquid form the weighed amount of drug was added to the liquefied carrier and stirred vigorously to get homogenous mixture and to get uniform coating of the carrier around the drug, then the homogenous mixture was cooled at room temperature to solidify the formulation. The final formulation was then evaluated by DSC, X-RD, FTIR, and HPLC to determine the polymorphic changes in the candesartan cilexetil. It was also evaluated to see whether there is any change in the release of the candesartan cilexetil.

Results: Evaluating the final formulation of the candesartan cilexetil solid dispersion by DSC, the endothermic peak of the formulation has shifted towards the lower temperature. When the formulation was characterized with X-RD the relative degree of crystallinity was found to 0.645, the crystallinity was not reduced in a drastic manner but it has given less intense peaks than the plain candesartan cilexetil. The evaluation by FTIR showed that shift in the peaks due change in polymorphism. HPLC evaluation has given the clear idea that the polymorphic changes have taken place in the formulation of candesartan cilexetil. In vitro release studies showed that the solid dispersion formulations have released the drug within 10minutes.

Conclusion: The solid state and, chromatographic characterization of the candesartan cilexetil solid dispersion formulation using melt method have confirmed that whenever the formulations are prepared with elevated temperature may leads to the polymorphic changes in the candesartan cilexetil.