Abhas Tiwari

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.