Monitoring of carbamazepine and carbamazepine 10,11-epoxide in breast milk and plasma by high-performance liquid chromatography

Abstract

A high-performance liquid chromatographic method was developed for the measurement of carbamazepine (CBZ) and carbamazepine 10,11-epoxide (CBZE) in human breast milk and plasma. The method involves rapid C18 solid-phase extraction of CBZ and CBZE. Chromatographic separation was achieved with a reversed-phase C8 column using a mobile phase of potassium dihydrogenphosphate (pH 2.5) and acetonitrile (67:33 v/v), with ultraviolet detection at 254 nm. 2-Methyl CBZ was used as the internal standard. Determination of both CBZ and CBZE was possible in the range of 0.01-6.0 mg/L and 0.02-6.0 mg/L in milk and plasma, respectively. The recoveries of CBZ and CBZE added to the milk and plasma were 90.6-98.0% and 88.9-104.0%, respectively, with coefficients of variation less than 8.3% and 10.5%, respectively. The method has been used for drug level monitoring in milk and plasma samples obtained from CBZ-treated patients. The mean (SD) levels for CBZ in milk and plasma samples were 3.50 (0.4) mg/L and 6.18 (2.9) mg/L, and for CBZE were 1.28 (0.3) mg/L and 1.85 (1.0) mg/L, respectively. The mean (SD) milk/plasma ratios of CBZ and CBZE were 0.64 (0.2) and 0.79 (0.3), respectively. The milk/plasma ratio of CBZE was slightly higher than that of CBZ.

High-Performance Liquid Chromatographic Determination of Fluvoxamine and Fluvoxamino Acid in Human Plasma

“…18,19 Our simple solid-phase extraction method, an efficient combination system in HPLC determination method, could remove interfering substances. [20][21][22][23] Therefore, we have examined solid-phase extraction procedures in detail for the purpose of eliminating such endogenous interference peaks.…”

“…We have reported a simple extraction method of several drugs and their metabolites by using a solid phase extraction cartridge. [20][21][22][23] However, an off-line solid phase extraction method for fluvoxamine has not been reported in previous papers. There is also no report for simultaneous determination of fluvoxamine and fluvoxamino acid in human plasma by HPLC.…”

Determination of Estazolam in Plasma by High-Performance Liquid Chromatography with Solid-Phase Extraction

“…[8][9][10] However, we have shown that the C8 analytical column, which provides a more efficient resolution and a shorter analytical time than the C18 phase, has a greater efficacy for the analysis of several drugs by the HPLC method. [14][15][16] Therefore, the C8 analytical column was used for our present HPLC analytical method in plasma estazolam. The retention times for estazolam and 527 ANALYTICAL SCIENCES MAY 2002, VOL.…”

“…We recently reported on HPLC analytical methods for several drugs by using a C8 analytical column. [14][15][16] More efficient separation and a shorter analytical time were obtained in the C8 HPLC column than in the C18 column, depending on the properties of the analytical drugs. We have appreciated the benefit of the C8 column in drug analysis by HPLC.…”

“…We have appreciated the benefit of the C8 column in drug analysis by HPLC. [14][15][16] In the present paper, we describe a rapid and simple solid-phase extraction method and selective HPLC method for the determination of estazolam levels in human plasma. The method was applied to studies of pharmacokinetics of estazolam in healthy volunteers.…”