Evaluation of Compatibility of Tablet Excipients with Albendazole and Closantel Using DSC and HPLC

Abstract The compatibility between albendazole and closantel, with commonly used tablet excipients, was assessed by studying drug-excipient mixtures mixed in 1:1 ratio and 1:1 ratios granulated with water and dried at 50°C for 1 hr with a differential scanning calorimeter (DSC) and high-performance liquid chromatograph (HPLC). Results showed that there were interactions between closantel and/or albendazole and some tablet excipients. For example, magnesium stearate reacted with both drugs and the interaction was observed by DSC and HPLC. Exposure of mixtures, and even the drugs, to heat and moisture resulted in deteriorated compatibility as seen by both DSC and HPLC, but especially HPLC. Overall poor correlation between DSC and HPLC results was observed.