Determination of heptaminol in plasma by thin-layer chromatography and in situ fluorimetry

A method has been developed for the determination of heptaminol in plasma samples. The main steps involved in the assay are: ethereal extraction at an alkaline pH; concentration of the extracted heptaminol as its hydrochloride; formation of a fluorescent derivative by reaction with 4-chloro-7-nitrobenzo-2,1,3-oxadiazole; separation of the fluorophore by thin-layer chromatography and in situ quantitation of the emitted fluorescence by photodensitometry. The sensitivity limit is estimated to be 25 ng ml(-1) plasma, the overall recovery is 81% and the relative standard deviation is 6% at 200 ng ml(-1). The assay is useful in studies on the pharmacokinetics of heptaminol in animals or man after administration of therapeutic doses. Plasma levels of the drug following administration of 5 mg.kg(-1) to rats are reported.