Bioequivalence of ritodrine hydrochloride tablets in Chinese healthy volunteers

Objective:To investigate the bioequivalence of different ritodrine tablets produced by different manufacturers.Methods: According to the similarity of height and weight,a biperiodic two cross test was designed.Totally 18 healthy female subjects were orally administered with 2 pieces(10 mg per piece) of test or reference ritodrine hydrochloride tablets.Then,ritodrine HCl concentrations in plasma were determined by LC-MS/MS method with an internal standard.The pharmacokinetic parameters were calculated using the DAS 2.0.1 software,and the bioequivalence of the two preparations was evaluated.Results: The pharmacokinetic parameters of reference tablets were t1/2=(2.623±1.223) h,Cmax=(12.425±6.891) ng·mL-1,Tmax=(0.769±0.555) h,AUC0~t=(28.416±9.102) ng·h·mL-1,AUC0~∞=(33.199±12.338) ng·h·mL-1;those of test tablets were t1/2=(2.539±0.670) h,Cmax=(14.475±11.262) ng·mL-1,Tmax=(0.741±0.509) h,AUC0~t=(30.499±11.402) ng·h·mL-1,AUC0~∞=(34.258±12.094) ng·h·mL-1.The relative bioavailability of the test tablets was(109.6±23.0)%(AUC0~t) or(108.0±26.2)%(AUC0~∞).Conclusion: The test and reference ritodrine hydrochloride tablets are bioequivalent.