High performance liquid chromatographic determination of a new biologically active 1,2,4-oxadiazine derivative in rat plasma.

A sensitive high performance liquid chromatographic procedure was developed for the determination of 3-phenyl-6-(1,2,3,4-tetrahydro-2-isoquinolyl)methyl-4H-5,6-dihydro -1,2, 4-oxadiazine a new vasodilator, in plasma. Rat plasma samples were made alkaline with ammonia and partitioned with chloroform. The extracts were dried with anhydrous sodium sulphate and evaporated to dryness under reduced pressure. The residues were redissolved in chloroform, and then chromatographed on silica column with chloroform/isopropanol (7:3, v/v). Detection was performed with a variable-wavelength UV detector set at 265 nm. Limit of identification was 10 ng, that of quantitative determination 50 ng 1/ml of plasma. The utility of the method for pharmacokinetic studies in the rat was demonstrated.