Application of thermal analysis in the characterization of anti-hypertensive drugs

The present work reports studies of the thermal behaviour of some anti-hype rtensive drugs. Their purities were determined by DSC and specialized pharm acopeial methods. The thermogravimetric data allowed determination of the k inetic parameters: activation energy, frequency factor and reaction order. The activation energy values suggest the following sequence of stability: n ifedipine>propanolol hydrochloride>captopril. Analysis of the DSC data indi cated that the degrees of purity of nifedipine, captopril and propanolol hy drochloride were similar to those found by pharmacopeial methods BP 93 and USP 23. The simplicity, speed and low operational costs of thermal analysis justify its application in the quality control of pharmaceutical drugs.