Thermal behavior of anti-hypertensives drugs in solution and human plasma using DSC-cooling

The present study proposes the use of DSC-cooling as a fast tool to evaluate the drug behavior in biofluids submitted to freeze-thaw studies. Captopril, captopril+ascorbic acid and propranolol in plasma were submitted to 3 cycles of freeze-thaw using DSC-cooling up to 243 K. Captopril-plasma has suffered calorimetric alteration and revealed a considerable interaction front to freezing and heating processes. The presence of additive can stabilize the analyte in plasma. Propranolol-plasma presented reducing in phase transition enthalpy comparable to the plasma denatured by perchloric acid in the last cycles of freezing. DSC-cooling data demonstrated great potentiality for the freeze-thaw studies of drugs in biofluids. This revised version was published online in July 2006 with corrections to the Cover Date.