Hydrochlorothiazide

A new selective, sensitive and Rapid Reverse phase-UPLC method was developed and validated to determine the known potential impurities present in Telmisartan (TL) and Hydrochlorothiazide (HC) in fixed dose combination drug product. The quantification was carried out by using Acquity UPLC, HSS T3 (100 × 2.1) mm, 1.8m column, with a flow rate of  0.5mL/min at 225 nm .The mobile phase consists of 0.1% ortho phosphoric acid pH adjusted to 2.6 with diluted sodium hydroxide as Mobile phase A and acetonitrile as Mobile phase B. Separation of the impurities was achieved within 10.0 minutes of run time. Typical retention times of TL and HC were found to be about 5.4 and 2.0 minutes respectively. The product was subjected to various degradation conditions and validated in terms of linearity, precision, accuracy, LOD, LOQ and robustness in accordance with ICH guidelines. The known impurities quantified in this study were HC imp-1 to 4 for Hydrochlorothiazide and TL imp-1 to 6 for Telmisartan. Recovery was established for all the impurities with respective to LOQ to 150%. The data supports that the newly developed method is capable to determine all the potential impurities of TL and HC.

A specific, sensitive and rapid LCMS/MS method was developed for simultaneous determination of olmesartan and hydrochlorothiazide in human plasma using olmesartan D4 and hydrochlorothiazide 13C6 as internal standards. Solid-phase extraction (SPE) method was used to extract the analytes from biological matrix. Analysis was carried out on phenomenex Luna C18 column with a flow rate of 0.600 mL/minute with 80% flow splitting. Detection was carried out on a triple quadrupole linear mass spectrometer, equipped with turbo ion spray source. The method was validated over the concentration range of 32.32 ng/mL to 2676.60 ng/mL for olmesartan and 5.12ng/mL to 423.83ng/mL for hydrochlorothiazide. Olmesartan and hydrochlorothiazide were found to be stable upto 75 days in K3EDTA based Human Plasma at -20ºC. Inter and intra-batch precision of olmesartan and hydrochlorothiazide were less than 15% and the accuracy was within 85–115% in plasma.  The mean % recovery was 53.09 % for olmesartan and 59.12 % for hydrochlorothiazide in human plasma. The stability of olmesartan and hydrochlorothiazide in plasma were confirmed up to five freeze-thaw cycles at -20°C and on bench up to 24 hours and 15 minutes at ambient temperature. The method was validated satisfactorily and was suitable for the quantitation of olmesartan and hydrochlorothiazide from plasma samples in a pharmacokinetic study.

Triamterene is a potassium-sparing diuretic which is commonly used in combination with Hydrochlorothiazide, a thiazide-type diuretic in clinical management of edema and moderate hypertension. In this study, a rapid and sensitive LC–MS/MS method was developed and validated for determination of Triamterene and Hydrochlorothiazide from K3EDTA based Human Plasma. Triamterene D5 and Hydrochlorothiazide 13C6 were used as an Internal Standards for analysis of Plasma Samples.  The analytes and internal standards, were extracted by liquid–liquid extraction method using Se Quant®ZIC-HILIC, (5um,200A 150 X 4.6 mm)  column with Acetonitrile and 2 mM Ammonium formate containing 0.1% formic acid (80:20 v/v) as the mobile phase. Linearity was assessed from 3.10ng/mL to 229.72 ng/mL for Triamterene and 5.47 ng/mL to 405.27 ng/mL for Hydrochlorothiazide in plasma.  No significant matrix effects were observed by analysing the plasma samples on LC–MS/MS. The accuracy was in the range of 98.32 % to 102.86 % for both compounds. Triamterene and Hydrochlorothiazide were found to be stable up to 120 days in K3EDTA based Human Plasma at -20ºC. The stability of Triamterene and Hydrochlorothiazide in plasma was confirmed up to five freeze-thaw cycles (−20°C) and on bench up to 25 hours. The proposed bioanalytical method for the quantitation of Triamterene and Hydrochlorothiazide from K3EDTA based human plasma samples was satisfactorily validated. It can be used to include study data for quantitation of Triamterene and Hydrochlorothiazide from K3EDTA based human plasma in bioequivalence and bioavailability study.

A simple and precise stability indicating RP-HPLC method was developed and validated for the simultaneous determination of Hydrochlorothiazide (HCTZ) and Nebivolol Hydrochloride (NBV) inbulk and Pharmaceutical dosage forms. Chromatography was carried out on Thermo Hypersil BDS C 18 (150 x 4.6 mm, 5mparticle size) column using a mobile phase of phosphate buffer (adjusted to pH 6.5 with dilute orthophosphoric acid): acetonitrile (40:60% v/v) at a flow rate of 0.8 ml/min. The analyte was monitored using PDA detector at 282 nm. The retention time was found to be2.4 min and 4.0min for Hydrochlorothiazide and Nebivolol Hydrochloride respectively. The proposed method was found to be having linearity in the concentration range of 6.25-37.5 µg/ml for Hydrochlorothiazide (r2 0.9999) and 2.5-15 µg/ml for Nebivolol Hydrochloride (r2 0.9999) respectively. The mean % recoveries obtained were found to be 99.93 % for Hydrochlorothiazide and 100.03% for Nebivolol Hydrochloride respectively. Stress testing which covered acid, alkali, peroxide, photolytic and thermal degradation was performed on under test to prove the specificity of the method and the degradation was achieved. The developed method has been statistically validated according to ICH guide lines and found to be simple, precise and accurate with the prescribed values. Thus the proposed method was successfully applied for the stability indicating simultaneous determination of Hydrochlorothiazide and Nebivolol Hydrochloridein bulk and Pharmaceutical formulations and in routine quality control analysis.

A simple and precise reversed-phase high performance liquid chromatography (HPLC) method for the determination of hydrochlorothiazide (HCT) in human plasma was developed and validated. Using hydroflumethiazide as an internal standard (IS), separation was achieved on Atlantis dC 18 column. The mobile phase, 10 mM monobasic potassium phosphate and acetonitrile (80:20, v: v), was delivered at a flow rate of 1.2 ml/min. The eluent was monitored by photodiode array detector, with the wavelength set at 272 nm. Plasma samples containing HCT and IS were extracted with methyl tert butyl ether and reconstituted in mobile phase. No interference in blank plasma or of commonly used drugs was observed. The relationship between the concentration of HCT in plasma and peak area ratio of HCT to the IS was linear over the range of 5-300 ng/ml. The intra-day and inter inter-day coefficient of variation and bias were

A simple, specific, accurate and precise reverse phase high performance liquid chromatographic (RP-HPLC) method was developed with high sensitivity for determination of Valsartan and Hydrochlorothiazide drugs in combined dosage forms. The separation was achieved on Zorbax CN (25 cm x 4.6 mm, 5 µm) at flow rate of 1.8 ml/min with 70: 30 mixture of phosphate buffer: acetonitrile (pH 6) as the mobile phase. The quantification was achieved with PDA detector at 265 nm. The injection volume was 20 μl. The retention times of Valsartan and Hydrochlorothiazide were 6.04 min and 2.27 min, respectively. The method was validated for linearity, precision, specificity, robustness and recovery according to the ICH guidelines. The linearity of response for Valsartan and Hydrochlorothiazide were assessed by analysis of five independent levels of calibration curve in range of 20-100 µg/ml and 2-10 µg/ml respectively. The recovery data was between 98.77-99.73% and 98.75-100.56% for Valsartan and Hydrochlorothiazide respectively. The limit of detection and quantification for Valsartan were 0.98 and 2.97μg/ml respectively and for Hydrochlorothiazide were 0.18 and 0.57μg/ml, respectively. The method was found to be simple and highly sensitive and can be useful in the routine quality control of Valsartan and Hydrochlorothiazide in bulk manufacturing and pharmaceutical dosage forms.

A HPLC method for simultaneous estimation of Ramipril and Hydrochlorothiazide in tablets was developed and validated. The developed method involves Purosphere® Star Rp18e, 5μm, 150×4.6mm column with mobile phase composition of acetonitrile and sodium perchlorate (pH 2.5) buffer in the ratio of 3:2, at a flow rate of 1.0 ml/min and UV detection at 316nm for first five minutes for Hydrochlorothiazide and 210nm for Ramipril. The method was validated as per ICH guidelines, Linearity was observed over concentration range of 17.5 to 32.5 µg/ml for Ramipril and 87.5 to 162.5 µg/ml for Hydrochlorothiazide. The Accuracy of the proposed method was determined by recovery studies and found to be 97.95-102.3% and 97.98-102.66% for Ramipril and Hydrochlorothiazide respectively. The proposed method was extended for estimation of Ramipril and Hydrochlorothiazide in marketed tablet formulation (Ramace-HTM) and it was found to be well within the acceptance limit. The developed and validated HPLC method for simultaneous estimation of Ramipril and Hydrochlorothiazide was found to be linear, accurate, precise, robust and rugged. Hence it can be used for routine analysis of Ramipril and Hydrochlorothiazide in tablets.

Two new, rapid, precise, accurate and specific chromatographic methods for the simultaneous determination of Olmesartan medoxomil and Hydrochlorothiazide in combined pharmaceutical dosage forms. The first method based on reverse phase liquid chromatography by using INERTSIL ODS C18 3V (150 x 4.6, 5μ) using mobile phase 1ml triethanolamine in one litre water and the pH was adjusted to 2.5 with orthophosphoric acid and acetonitrile using a gradient program with a flow rate of 1ml/min, throughout the gradient program with a detection wavelength of 225nm.The second method involved silica gel 60F254 high performance thin layer chromatography and densitometric detection at 270nm using chloroform : methanol(85:15) as the mobile phase