SIM-6080

A sensitive and selective gas chromatographic method for the determination of the calcium antagonist SIM6080 in plasma has been developed and validated. A three-step extraction procedure is employed followed by capillary gas chromatographic analysis using nitrogen-selective detection and the programmed temperature vaporizer injection technique. The defluorinated analogue was used as the internal standard. The analysis of spiked plasma demonstrated the good accuracy and precision of the method with limit of detection of 1 ng/ml. The method has been used for pharmacokinetic studies in laboratory animals.

SIM 6080 is a new calcium antagonist, structurally related to diphenylalkylamines, which combines transmembrane and intracellular calcium antagonist activities. In the present study we investigated the effect of SIM 6080 on atherogenesis in cholesterol-fed rabbits. Subcutaneous administration of the compound at 0.33, 1, and 3 mg kg-1/bid for 60 days neither affected plasma lipids nor blood pressure. However at 1 and 3 mg kg-1/bid SIM 6080 reduced in a dose-dependent manner both the area of the aorta covered by plaques and aortic cholesterol content. Determination of SIM 6080 plasma and aortic content indicated that the compound could concentrate up to 10 times in the arterial tissue. In vitro studies demonstrated that at concentrations similar to those observed in the aorta this compound may stimulate rabbit beta VLDL catabolism by smooth muscle cells in an homologous system suggesting that the up-regulation of LDL-receptors in the aorta may contribute to the antiatherosclerotic properties of SIM 6080.