Bioequivalence and pharmacokinetics of spironolactone tablets in healthy volunteers

Objective To study the pharmacokinetics and bioavailability of spironolactone tablets in healthy volunteers.Methods A cross-over,randomized study was performed in 18 healthy male volunteers receiving a single oral dose of 25 mg of the tested or the referenced spironolactone tablets.A sensitive and specific HPLC-MS method was developed to quantitate the concentrations of canrenone in plasma,which is one of the major active metabolites of spironolactone.The pharmacokinetic parameters were analysed by two one-side t test to determine the bioequivalence of the two preparations.Results The main pharmacokinetic parameters of the tested and the referenced preparations were as follows: AUC0→72were(684.8±184.4)μg·h·L-1and(682.1±212.7)μg·h·L-1,AUC0→∞were(803.8±249.6)μg·h·L-1and(774.3±259.3)μg·h·L-1,tmax were(2.1±0.3)h and(1.9±0.4)h,Cmax were(51.3±12.4) μg·L-1and(54.1±12.9)μg·L-1,t1/2were(25.0±9.2) h and(22.1±6.0)h.The relative bioavailability of canrenone was(102.2±19.0)%.Conclusion The tested and the referenced preparations are bioequivalent.