Comparison of generic hydrochlorothiazide formulations by means of TG and DSC coupled to a photovisual system

The compatibilities and stabilities of some binary mixtures and generic hyd rochlorothiazide formulations were studied by using TG, DSC and a DSC-photo visual system. The kinetic parameters were determined via the Arrhenius equ ations. Tablet B presented higher compatibility and thermal stability than those of tablets A and C. The photovisual system demonstrated that the deco mposition of tablet A occurs before the melting point, due to the Maillard reaction between the hydrochlorothiazide and lactose present in the formula tion. The behaviour and rate constants of binary mixtures suggest that lact ose can be substituted for microcrystalline cellulose, MC(101), in tablet A . The DSC and TG data revealed different characteristics of compatibility a nd stability in generic formulations from different manufacturers.