High-performance liquid chromatographic analysis of cyclosporin G (Nva2-cyclosporine) in human blood.

A sensitive high-performance liquid chromatographic method for the analysis of the immunosuppressant cyclosporin G (OG 37-325, Nva2-cyclosporine, CsG) in whole blood has been developed. Sample preparation, employing cyclosporin A (CsA) as internal standard, involves organic extraction with methyl t-butyl ether under sequential acidic and basic conditions. Chromatography is performed using a 2 mm inside diameter x 25 cm column packed with 5 microns octyl (C8) material. An isocratic mobile phase comprised of acetonitrile:methanol:water, at a flow rate of 0.4 ml/min, is utilized. Separation is monitored at 230 nm. Data are also presented that demonstrate the use of CsG as an alternative internal standard to cyclosporin D for liquid chromatographic determinations of CsA.