Phase quantification of antihypertensive drugs – Chlorthalidone, Hydrochlorothiazide, Losartan and combinations, Losartan/Chlorthalidone and Losartan/Hydrochlorothiazide – by the Rietveld method

•Quantitative analysis has been realized for antihypertensive drugs and associations.•Specifically, Losartan potassium, Chlorthalidone, Hydrochlorothiazide.•The drugs have been characterized X-ray powder diffraction.•Rietveld method has been performed. The identification and quantification of crystalline phases of antihypertensive drugs – Losartan potassium (LOS-K), Hydrochlorothiazide (HCTZ) and Chlorthalidone (CTD) were carried out by means of X-ray powder diffraction data and the Rietveld method. Quantitative phase analyses of Losartan potassium/Chlorthalidone (LOS-K/CTD) and Losartan potassium/Hydrochlorothiazide (LOS-K/HCTZ) combinations were also evaluated. The results indicated that for diuretics (HCTZ and CTD) only one crystalline phase was found in samples, and for LOS-K the crystal structure showed similarity between the Bragg peaks to the phase described as monoclinic and space group P21/c. After one year storage, the orthorhombic one was also observed in this sample.