A fluorometric method for the determination of praziquantel in blood-plasma and urine

Some physicochemical data of praziquantel which may have analytical relevance are reported. For the quantitative determination praziquantel is extracted from plasma or urine by means of organic solvents and then hydrolyzed in an aqueous alkaline solution. The hydrolyzed product is reacted with dansyl-chloride (5-dimethylaminonaphthalene-sulfonylchloride). The dansylated compound is separated and quantified fluorometrically. The limit of determination is 3 micrograms/l in blood plasma and 30 micrograms/d in urine. For both fluids, the imprecision is approximately 7.5%. The method is suitable for the determination of praziquantel in patients or healthy volunteers treated with therapeutic doses.