Authors:Dorota Kowalczuk, Hanna Hopkała, and Rafał Pietraś
A new, simple, and accurate TLC method, using normal- and reversed-phase techniques and densitometric detection, has been developed for measurement of quinapril and hydrochlorothiazide in combination tablets. UV detection at
= 210 nm was used to quantify the analytes. The drugs were chromatographed on silica gel 60 F
HPTLC plates and on octadecilsilane (RP-18) TLC plates, in horizontal chambers, with ethyl acetate-acetone-acetic acid, 8 + 2 + 0.5 (
) and methanol-0.07 m
phosphate buffer, pH 2.5, 6 + 4 (
), respectively, as mobile phases. The active substances were extracted from tablets with methanol (96% < mean recovery < 104%). Calibration curves were constructed in the range 0.4 to 2.4 μg μL
for quinapril and 0.25 to 1.5 μg μL
for hydrochlorothiazide, with good correlation (
≥ 0.998). The precision (
< 4.4%) and accuracy (2.91 <
< 3.92) were satisfactory for TLC-densitometric determination of quinapril in combination with hydrochlorothiazide in commercial tablets.
A rapid and simple method has been developed for chromatographic separation of the pharmacologically active components of some antihypertensive drugs. The active compounds — lisinopril, cilazapril, captopril, quinapril, and ramipril — were successfully separated on aminoplast layers with benzene-cyclohexane-methyl ethyl ketone, 15 + 10 + 15 (
), as mobile phase. The mechanism of retention and the correlation between lipophilicity and log
were both investigated.