3 research outputs found
RP-LC and HPTLC Methods for the Determination of Olmesartan Medoxomil and Hydrochlorothiazide in Combined Tablet Dosage Forms
Two new, rapid, precise, accurate and specific chromatographic methods were described for the simultaneous determination of olmesartan medoxomil and hydrochlorothiazide in combined tablet dosage forms. The first method was based on reversed phase liquid chromatography using an Eurosphere 100 RP C18 column (250 × 4.6 mm ID, 5 μm). The mobile phase was methanol–0.05% o-phosphoric acid (60:40 v/v) at a flow rate of 1.0 mL min−1. Commercially available tablets and laboratory mixtures containing both drugs were assayed and detected using a UV detector at 270 nm. The second method involved silica gel 60 F254 high performance thin layer chromatography and densitometric detection at 254 nm using acetonitrile–ethyl acetate–glacial acid (7:3:0.4 v/v/v) as the mobile phase. Calibration curves ranged between 200–600 and 125–375 ng spot−1 for olmesartan and hydrochlorothiazide, respectively
Simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in tablets by second-order derivative spectrophotometry
A second-order derivative spectrophotometric method for the simultaneous
determination of benazepril hydrochloride and hydrochlorothiazide in
pharmaceutical dosage forms is described. The determination of
benazepril hydrochloride in the presence of hydrochlorothiazide was
achieved by measuring the second-order derivative signals at 253.6 and
282.6 nm, while the second-order derivative signal at 282.6 nm was
measured for the determination of hydrochlorothiazide. The linear
dynamic ranges were 14.80-33.80 mu g ml(-1) for benazepril hydrochloride
and 18.50-42.20 mu g ml(-1) for hydrochlorothiazide, the correlation
coefficient for the calibration graphs were better than 0.9998, n = 5,
the precision (%RSD) was better than 1.43% and the accuracy was
satisfactory (E-r < 0.99%). The detection limits were found to be 2.46
and 1.57 mu g ml(-1) for benazepril hydrochloride and
hydrochlorothiazide, respectively. The method was applied in the quality
control of commercial tablets and proved to be suitable for rapid and
reliable quality control. (C) 1999 Elsevier Science B.V. All rights
reserved
Simultaneous determination of benazepril hydrochloride and hydrochlorothiazide by micro-bore liquid chromatography
A micro-bore liquid chromatographic method was developed for the
simultaneous determination of benazepril hydrochloride and
hydrochlorothiazide in pharmaceutical dosage forms. The use of a BDS
C-18 micro-bore analytical column, results in substantial reduction in
solvent consumption and increased sensitivity. The mobile phase
consisted of a mixture of 0.025 M sodium dihydrogen phosphate (pH 4.8)
and acetonitrile (55:45, v/v), pumped at a flow rate of 0.40 ml min(-1).
Detection was set at 250 nm using an ultraviolet detector. Calibration
graphs are linear (r better than 0.9991, n = 5), in concentration range
5.0-20.0 mu g ml(-1) for benazepril hydrochloride and 6.2-25.0 mu g
ml(-1) for hydrochlorothiazide. The intra- and interday R.S.D. values
were < 1.25% (n = 5), while the relative percentage error (E-r) was <
0.9% (n = 5). The detection limits attained according to IUPAC
definition were 0.88 and 0.58 mu g ml(-1) for benazepril hydrochloride
and hydrochlorothiazide, : respectively. The method was applied in the
quality control of commercial tablets and content uniformity test and
proved to be suitable for rapid and reliable quality control. (C) 1999
Elsevier Science B.V. All rights reserved