Hydrochlorothiazide

For the assessment effect of food on the pharmacokinetic parameters of Hydrochlorothiazide(HCTZ) data of reference product (12.5 mg capsule) from two bio-equivalence studies were combined and evaluated. 36 male healthy subjects participated in the fasting and non fasting study. Subjects received the drug product after 12 hours(h) overnight fast for the fasting study and after 30.0 minutes of high fat  breakfast for the non-fasting study. Blood samples were collected from time of dosing to 60 h of the post dosing at predefined time. Blood samples were analyzed for the concentration of the HCTZ by using validated LC/MS/MS technique. Food decrease the Cmax by about 28% and AUC by about 9%. While Tmax was delayed about 97%(from 2.185h to 4.320h). food prolonged the mean resident time of HCTZ. 

A simple, accurate, precise and fast reverse phase, gradient RP-HPLC method was developed for the separation of telmisartan and hydrochlorothiazide in combination dosage form of Tablets. The method was carried out by using Kromasil, C18, 4.6 x 150mm, 5 μm enhanced polar selectivity column and mobile phase comprised of potassium dihydrogen phosphate buffer pH adjusted to 3.2 ± 0.5 with orthophosphoric acid and acetonitrile, and degassed under ultrasonication. The flow rate was 1.5 mL/min and the effluent was monitored at 225nm. The retention time of hydrochlorothiazide and telmisartan were 2.7 ± 0.5 and 7.3 ± 0.5 respectively. The method was validated as per ICH guideline. The proposed method is suitable for simultaneous determination of telmisartan and hydrochlorothiazide in pharmaceutical dosage form.