High-performance liquid chromatographic method for the quantification of several diamidine compounds with potential...

A high-performance liquid chromatographic method has been developed for the detection and quantification of pentamidine and pentamidine analogues of chemotherapeutic value in order to measure their concentration in physiological fluids. The compounds were extracted from urine over octadecyl solid-phase extraction columns, followed by chromatographic separation with an octadecyl reversed-phase column. For the mobile phase, a gradient of 31.5-37.5% acetonitrile in water, with sodium heptanesulfonate and tetramethylammonium chloride as ion modifiers, was used. This method was used to reliably detect levels as low as 341 ng/ml without concentration of the compounds during the solid-phase extraction. The assay was used to determine the effectiveness of several solid-phase extraction columns for isolating the compounds of interest and to quantify the amount of pentamidine and its analogues contained in the urine of dosed rats.