Quantitative thin-layer and high-performance liquid chromatographic determination of the diuretic agent 2-chloro-5-[44-hydroxy-3-methyl-2-(methylimino)-4-thiazolidinyl]benzenesulphonamide hydrochloride in serum and urine.

Sensitive and specific thin-layer (TLC) and high-performance liquid chromatographic (HPLC) methods were developed for the determination of the diuretic agent 2-chloro-5-[4-hydroxy-3-methyl-2-(methylimino)-4-thiazolidinyl]benzenesulphonamide hydrochloride (HOE 740). HOE 740 can be determined in serum by HPLC. The detection is performed at a very short wavelength (202 nm), resulting in a detection limit of 10 ng/ml. By TLC only urine levels that are normally high can be determined directly (the detection limit is 70 ng/ml). For the determination of the lower serum levels it is necessary to convert the drug into its dehydration product, which has a higher absorbance and gives sufficient sensitivity (the detection limit is 10 ng/ml). Serum levels determined by the two methods correlate well. Some pharmacokinetic and excretion-kinetic data were computed using two-compartment open models.