Montmorillonite as an agent for drug photostability

Abstract

Among the large number of applications of montmorillonite and halloysite, low attention has been devoted to the photostabilization effect of these matrices on photounstable agents and no studies have been performed concerning their employment for drug photostability improvement. Herein we report the preparation of novel hybrids of these inorganic matrices and piroxicam (PX), which was chosen as a model drug due to its instability to light. The hybrid materials were successfully prepared with high drug loading and then were characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and FT-IR spectroscopy. Finally, in order to investigate the matrix effects on piroxicam photostability, the hybrids were subjected to spectrophotometric analysis as a function of light exposure time. The results highlighted that PX intercalation into montmorillonite markedly improves the drug photostability and that this matrix can be proposed as an excipient for drug photostability enhancement.