Simultaneous determination of carbamazepine and its metabolites in plasma from carbon tetrachloride-intoxicated rats using a new reversed-phase chromatographic column of 2-microns porous microspherical silica gel.

A high-performance liquid chromatographic method has been developed for the simultaneous analysis of carbamazepine (CBZ) and its two metabolites, carbamazepine-10,11-epoxide (CBZ-E) and carbamazepine-10,11-dihydroxide (CBZ-diOH), using a recently developed reversed-phase column with 2-microns particles and a 2-microliters microflow cell equipped with a UV detector. The separation was achieved using two different C18 reversed-phase columns (column 1: 100 x 4.6 mm I.D., particle size 2 microns, TSK gel Super-ODS; column 2: 100 x 4.6 mm I.D., particle size 5 microns, Hypersil ODS-C18) for comparison. The mobile phase was composed of methanol-water (30:70, v/v), and the flow-rate was 0.4 ml/min for both columns. The absorbance of the eluent was monitored at 210 nm. Retention times with column 1 were shorter than with column 2. When the three compounds were determined, the sensitivity and limit of quantification were about ten times better with column 1 than with column 2. The relative recovery and linearity with column 1 were approximately the same as those with column 2. These results show that the new ODS column packing with a particle size of 2 microns gives a higher sensitivity and shorter analysis time than the conventional ODS column packing.