Praziquantel is an anthelmintic drug effective against flatworms. The drug is used to treat diseases in humans, mammals, and fish. Praziquantel and related impurities can be analyzed by reversed-phase chromatography according to the USP, United States Pharmacopeia, manuscript. It requires a reversed-phase HPLC column, classified as L1. This method was developed on the Legacy L1 column and can be used for analysis of various molecules according to USP.