Determination of the calcium antagonist flunarizine in biological fluids by gas-liquid chromatography.

A method is described for the quantitation of flunarizine in biological fluids including plasma, urine, milk, fecal and tissue homogenates using the analogue cinnarizine as the internal standard. As little as 1.5 ng of flunarizine per ml of plasma can be accurately quantitated, this being achieved by the combination of a selective extraction procedure and a nitrogen detector. The method has been used to determine the concentration of flunarizine in biological fluids in support of human and animal pharmacokinetic studies.