DETERMINATION OF EQUILIBRIUM SOLID/VAPOUR PRESSURE VALUES OF FROZEN ORGANIC FORMULATIONS USED IN DRUGS FREEZE-DRYING PROCESSES BY THE THERMOGRAVIMETRIC METHOD

The vapour pressure of both solvents largely experimented for drugs freeze- drying, namely pure tert-butanol (TBA) and 90% (w/w) TBA + 10% (w/w) water mixture have been determined by using two different and comparative methods: the Thermogravimetric Method (TG Method) and the Static Method (SM). Both methods led to similar values with a relative deviation less than 2%. This validation proved that the new TG method is a rapid, reliable and precise technique for the determination of the equilibrium vapour pressures values of frozen organic formulations, values which are key parameters for physical modelling of freeze-drying processes.