Liquid-chromatographic analysis for cyclosporine with use of a microbore column and small sample volume.
This liquid-chromatographic assay requires 0.2 to 0.5 mL of whole blood, avoids the use of diethyl ether, and consumes only 10 to 20% of the solvents used in prior methods. Sample preparation involves an acidic extraction with methyl-t-butyl ether, performed in a 13 X 100 mm disposable glass tube, then a short second extraction of the organic phase with sodium hydroxide. After evaporation of the methyl-t-butyl ether, chromatography is performed on an "Astec" 2.0-mm (i.d.) octyl column. We compared results by this procedure with those by use of earlier larger-scale extractions and their respective 4.6-mm (i.d.) columns; analytical recoveries of cyclosporins A and D were comparable with previous findings and results for patients' specimens were equivalent, but the microbore columns provided greatly increased resolution and sensitivity.
D002853:Chromatography, Liquid / Q000295:instrumentation; D003524:Cyclosporins / Q000097:blood*; D004986:Ether; D006536:Heptanes; D006801:Humans; D008738:Methyl Ethers
D003524:Cyclosporins; D006536:Heptanes; D008738:Methyl Ethers; D004986:Ether