Liquid-chromatographic analysis for cyclosporine with use of a microbore column and small sample volume
Annesley, T.; Matz, K.; Balogh, L.; Clayton, L.; Giacherio, D.
Clinical Chemistry 32(7): 1407-1409
1986
ISSN/ISBN: 0009-9147 PMID: 3719953 Document Number: 279688
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.