Identification of methylated tubulin through analysis of methylated lysine

Investigation of Selective Ribavirin Extraction from Serum Samples Using a Monolithic Silica Disk-Packed Spin Column

Ribavirin, a nucleoside analog, is used to treat chronic hepatitis C (HCV) infections. Therapeutic drug monitoring for ribavirin is useful for predicting the effect of treatment. In this study, the selective extraction of ribavirin from serum samples and the HPLC-UV detection method were investigated using a monolithic silica disk-packed spin column with phenylboronate moieties. In this study, 0.6% ammonia and 1% formic acid solutions were used as the conditioning and elution solutions, respectively, and recoveries of >90% were obtained. Ribavirin was separated on an InertSustain AQ-C18 column by isocratic elution. The mobile phase consisted of a mixture of 7 mM Na2SO4 and 60 mM H3PO4 in H2O. Linear regression curves were observed for calibrations over a concentration range of 0.25–25 µg/mL. The lower limit of detection was 0.05 µg/mL, and the lower limit of quantification was 0.1 µg/mL. The intra- and inter-day precisions were below 3.2 and 3.1%, respectively. This method can be applied to quantify ribavirin levels in human serum and may be useful for pharmacokinetic studies.