Candesartan (CAND) is an active pharmaceutical ingredient used in the treatment of hypertension, acting as an angiotensin-receptor blocker, also being used in the treatment of myocardial infarction, heart failure, coronary artery disease and systolic dysfunction. In solid dosage forms, CAND is incorporated as a prodrug, namely candesartan cilexetil (CANDCEX, see structure in Figure 1), which undergoes in vivo hydrolysis, forming the active metabolite, CAND [1].figureFigure 1. Chemical structure of candesartan cilexetil Since solid dosage forms contain the prodrug (CANDCEX), in this study the decomposition kinetics was investigated for the pure prodrug vs. the prodrug in a pharmaceutical formulation with a strength of 16 mg per tablet using isoconversional methods (Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Friedman and NPK) at different heating rates. The influence of excipient effect is discussed for the thermal stability of prodrug in the solid commercial formulation.