High-performance liquid chromatographic column-switching method for two cyclosporine metabolites in blood
Gmur, D.J.; Meier, P.; Yee, G.C.
Journal of Chromatography 425(2): 343-352
ISSN/ISBN: 0021-9673 PMID: 3286668 DOI: 10.1016/0378-4347(88)80038-0
Cyclosporine (CSA) is biotransformed to many metabolites which may contribute to its immunosuppressive and nephrotoxic activity. We report a rapid and sensitive, automated column-switching high-performance liquid chromatographic (HPLC) method for measuring CSA-M17 in whole blood; the method also separates CSA-M1. CSA metabolite standards were isolated by a preparative-scale HPLC method. Samples were prepared by protein precipitation with acetonitrile followed by dilution with water. CSA-M17 was initially separated on a C8 column; final separation was on a C18 column. The inter-day relative standard deviation at 50 ng/ml was 8% (n = 3). Limit of detection was 20 ng/ml.