The goal of this project was to investigate the stability of the thiazide diuretics altizide, hydrochlorothiazide and chlorothiazide both in vitro and in vivo. Not only the
degradation of the parent drug was investigated also the formation of the degradation
compound 4-amino-6-chloro-1,3-benzen edisulponamide was monitored. The results of the in vitro studies show that the thiazides are degradated faster at higher pH and higher temperature. In particular the lower pH improves the stability. When altizide and hydrochlorothiazide were exposed to UV-light, they photodegradate to chlorothiazide. When the degradation rate between the different compounds was compared for a given temperature and pH, altizide is the most unstable compound. Concentrations ranged between 41-239 ng/mL and 60-287 ng/mL after altizide and hydrochlorothiazide administration, respectively