COMPATIBILITY STUDIES OF INDAPAMIDE/PHARMACEUTICAL EXCIPIENTS USED IN TABLET PREFORMULATION

Indapamide (IDP) is a non-thiazide sulphonamide diuretic drug, currently used for the treatment of essential hypertension. A pharmaceutical formulation is considered appropriate when no interactions drug-excipient or excipient-excipient occur. The purpose of the present work was to study the compatibility of IDP with the pharmaceutical excipients employed in immediate release tablets preformulations (2.5 mg/cp), by using thermoanalytical techniques (differential scanning calorimetry (DSC) and thermogravimetry (TG)) with the support of X-ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FTIR). In this respect, thermal analysis (DSC, TG), XRPD and FTIR methods were employed to evaluate the behaviour of IDP and excipients used in formulation (lactose monohydrate, microcrystalline cellulose, sodium amidonglycolate, polyvinylpyrrolidone, colloidal silicon dioxide (aerosil), magnesium stearate), but also its corresponding physical binary mixtures. FTIR, thermal analysis (DSC, TG) and XRDP methods applied to the mentioned physical mixtures did not show evidence of interactions in the solid state. Based on these results supplied by FTIR, DSC/TG and XRPD, all the excipients were found to be compatible with IDP, so they can be further used in the formulation of immediate release tablets.