Gas chromatographic determination of gallopamil and norgallopamil in human plasma.

A highly sensitive gas chromatographic assay is described for the simultaneous determination of gallopamil, a calcium channel blocking agent, and its major metabolite, norgallopamil. A multi-step extraction procedure is employed followed by on-column capillary gas chromatographic analysis using nitrogen-selective detection. Acetylation of norgallopamil is performed to enable accurate quantification of the metabolite. Linearity was achieved over the range 1-50 ng/ml for both analytes. Assay specificity, precision and accuracy were investigated.