A high-performance liquid chromatography and nuclear magnetic resonance spectroscopy-based analysis of commercially available praziquantel tablets

The amount of active ingredient in 20 commercially sourced batches of praziquantel (PZQ) tablets was determined using a high-performance liquid chromatography–ultraviolet (HPLC–UV) assay in conjunction with an anthentic, lot of PZQ powder. The general composition of each batch of tablets was also examined by means of 1H nuclear magnetic resonance (NMR) spectroscopy and the NMR data were subjected to pattern recognition analysis by means of principal component analysis. The HPLC–UV results showed that each batch of PZQ tablets contained approximately the required amount of PZQ (600 mg per tablet). The NMR analysis showed a high degree of compositional variation between manufacturers, which caused by variation in excipients, along with some batch-to-batch variation in the tablets from a single manufacturer. Additionally, the PZQ tablets from one manufacturer were found to have an extra component (methyl-4-hydroxybenzoate) that was not detected in the other preparations.