MICROBORE LIQUID-CHROMATOGRAPHY FOR ANALYSIS OF PLASMA PINDOLOL CONCENTRATIONS

Isocratic high-performance liquid chromatographic assay of pindolol with use of a microbore column was developed. The sample preparation involves extraction of alkalized plasma into ether and back extraction into 0.05 N H2SO4. Metoprolol was used as the internal standard. Chromatographic separation is performed on a microbore C18 (5-mu-m) column using acetonitrile-disodium hydrogenphosphate buffer (37:63) containing 20 mM sodium dodecyl sulfate as the mobile phase. The detection is achieved by using a fluorescence detector operated at the excitation and emission wavelengths of 260 and 310 nm, respectively. Acceptable reproducibility and accuracy data are presented over the concentration range normally encountered in human plasma samples. The lower detection limit is 2.5 ng/ml. This sensitivity has been found to be adequate for routine analysis of pindolol in human plasma samples, making the method applicable to pharmacokinetic studies and clinical trials.