Background: Atenolol is a selective beta 1 blocker that can be used alone or in combination
with hydrochlorothiazide or with chlorthalidone for the treatment of hypertension and prevention from a
Objective: The main target of this work was to improve modern, easy, accurate and selective liquid
chromatographic method (RP-HPLC) for the determination of these drugs in the presence of their degradation
products. These methods can be used as analytical gadgets in quality control laboratories for a
Methods: In this method, the separation was accomplished through an Inertsil® ODS-3V C18 column
(250 mm x 4.6 mm, 5 μm), the mobile phase used was 25 mM aqueous potassium dihydrogen orthophosphate
solution adjusted to pH 6.8 by using 0.1M sodium hydroxide and acetonitrile (77 : 23, v/v),
the flow rate used was 1 ml/min and detection was achieved at 235 nm using UV.
Results: All peaks were sharp and well separated, the retention times were atenolol degradation (ATN
Deg.) 2.311 min, atenolol (ATN) 2.580 min, hydrochlorothiazide degradation (HCT Deg.) 5.890 min,
hydrochlorothiazide (HCT) 7.016 min, chlorthalidone degradation CTD Deg 8.018 min and chlorthalidone
(CTD) 14.972 min. Linearity was obtained and the range of concentrations was 20- 160 μg/ml for
atenolol, 10-80 μg/ml for hydrochlorothiazide and 10-80 μg/ml for chlorthalidone. According to ICH
guidelines, method validation was accomplished, these methods include linearity, accuracy, selectivity,
precision and robustness.
Conclusion: The optimized method demonstrated to be specific, robust and accurate for the quality
control of the cited drugs in pharmaceutical dosage forms.