INVESTIGATION OF THE THERMAL-DECOMPOSITION OF SOME CALCIUM SALTS USEDIN MEDICINE

The thermal decomposition of several calcium salts of organic acids us ed in medicine - lactate pentahydrate, gluconate hydrate, lactoglucona te, pantothenate, cyclobarbital and cardiamid trihydrate was investiga ted. The analyses were performed using a derivatograph. Sample weights were from 20 to 200 mg, and heating rate from 3 to 15 K min(-1). Stat ic air atmosphere was used. It has been established, that the thermal decomposition of calcium salts occurs via several stages. The stages o f dehydratation of hydrates and of decarboxylation of calcium carbonat e are distinctly marked on the thermoanalytical curves, which may be u sed for the control of composition of the studied compounds. Moreover, tbe ranges of temperature, in which the analysed compounds can be tec hnologically transformed without change of their physicochemical prope rties, were established. A possibility of application of the Kissinger 's equation for calculating the parameters of the decomposition kineti cs was indicated as well. For chemometric evaluation of the results th e principal component analysis (PCA) was applied. By this method tile influence of heating rate and sample size on the thermal decomposition of the studied compounds was determined.