HPLC detection of thioperamide from biological samples and its determination in rat blood and brain after systemic administration.

Thioperamide is a potent and selective antagonist on histamine H3 receptors. A method for its isolation and quantitation by HPLC from rat plasma and brain samples has been developed. Using this technique, thioperamide concentrations in rat plasma and brain were measured after systemic administration, in order to evaluate its persistence in blood and its ability to cross the blood-brain barrier. We observed that, at a dose of 60 mg/Kg, thioperamide undergoes a slow elimination from plasma, with a half-life of 10 hours, and can readily cross the blood-brain barrier.