Influence of preparation technique on co-amorphization of carvedilol with acidic amino acids

In this study the basic drug carvedilol (CAR) and the two acidic AAs, glutamic acid and aspartic acid, were used to explore the possibilities of producing co-amorphous formulations using BM, SD and liquid assisted grinding (LAG). X-ray powder diffraction, thermal analysis and Fourier-transform infrared spectroscopy were used to determine the solid state form of the various CAR-AA mixtures prepared. BM the CAR-AA mixtures for 60 min did not result in co-amorphization as XRPD revealed remaining crystallinity of both CAR and the AA. On the other hand, successful co-amorphous salt formation was obtained for all SD samples. Differential scanning calorimetry showed that all the SD CAR-AA mixtures had a single glass transition temperature of approximately 80°C. The CAR-AA mixtures prepared by LAG showed some polymorphic conversion of CAR. Intrinsic dissolution testing showed the highest dissolution rate for all SD mixtures due to co-amorphous salt formation. Hence it was observed that of the three preparation techniques used, successful co-amorphous formulations of a basic drug with an acidic AA could only be prepared by SD.Graphical abstract
Source: International Journal of Pharmaceutics - Category: Drugs & Pharmacology Source Type: research