Pharmacokinetics and Drug-Drug Interaction of Allisartan Isoproxil and Indapamide Sustained-Release Formulation

Allisartan isoproxil (AI) is an angiotensin II type 1 receptor blocker and be converted into the active substance EXP3174 in vivo. We evaluated the drug-drug interactions of AI and an indapamide sustained-release (Ind SR) preparation, as well as the pharmacokinetic characteristics and safety of AI and Ind SR in healthy subjects. The trial was set up in 6 sequences and 3 cycles, and each cycle contained a 7-day washout period. Subjects received 3 different trial drugs (A, AI; B, Ind SR; C, AI + Ind SR) during 3 different cycles. Twenty-four subjects were enrolled in the clinical trial. Of these, 22 completed the study, 2 subjects dropped out due to adverse events (AEs). For subjects given AI alone or combined with Ind SR, the pharmacogenetic parameters C_max and the geometric mean ratio of steady state (combined/single) of EXP3174 was 130%. The geometric mean ratio of area under the concentration-time curve over the dosing interval at steady state (combined/single use) was 144.5%. Therefore, the combination of Ind SR had an impact on the pharmacokinetics of AI. Then, the results indicated that the AI combination had no effect on the pharmacokinetics of Ind SR. Serious AEs did not occur. The AEs in this clinical trial were the same as those for AI and Ind SR. Combined administration resulted in 2 cases (2 subjects) of Grade 3 hypotension and 1 case of Grade 3 hypotension with AI alone. Considering that this trial included healthy volunteers, the risk of hypotension was expected to be manageable.