Objective To determine the
pharmacokinetics of
erythromycin stinoprate capsules and to provide guidance for clinical research.
Methods Thirty healthy volunteers (15 men and 15 women) were divided into 3 groups randomly, each including 5 men and 5 women. Single oral doses of 250, 500 and 750 mg were given to each volunteer. The concentrations of erythromycin propionate and erythromycin base in the plasma were determined by HPLC-MS. Results All 30 volunteers completed the experiment without adverse reactions. Using 3P87 we analyzed the model and calculated the
pharmacokinetic parameters. Three dose groups taking high, middle and low dose were all single compartment model. The pharmacokinetic parameters of erythromycin propionate after taking
erythromycin stinoprate capsules were as follows: Low dose group: Ka (2.007±1.281)/h,t max (actual value)(1.9±0.6) h,C max (437.0±295.0) μg/L,AUC 0-14 (trapezoid area) (1840.2±1476.87) μg·h/L,Ke (0.329±0.119)/h,T 1/2 (2.45±0.9) h. Middle dose group: Ka (1.451±0.380)/h, t max (1.7±0.3) h, C max (923.1± 217.5) μg/L,AUC 0-14 (4542.4±1579.4) μg·h/L,Ke (0.237±0.057)/h,T 1/2 (3.1±1.1) h; High dose group: Ka (2.076±1.559)/h,t max (1.7±0.3) h,C max (1336.5±366.0) μg/L,AUC 0-14 (7481.5±2496.2) μg·h/L,Ke (0.266±0.051)/h,T 1/2 (2.7±0.5) h. The pharmacokinetic parameters of erythromycin were as follows: Low dose group: Ka (1.410±0.626)/h, t max (1.8± 0.5) h, C max (197.5±227.6) μg/L, AUC 0-14 (766.4±981.0) μg·h/L,Ke (0.519±0.240)/h, T 1/2 (1.6±0.8) h. Middle dose group: Ka (1.900±1.049)/h,t max (1.6±0.2) h,C max ( 488.3±216.7) μg/L,AUC 0-14 ( 488.3±216.7) μg/L,Ke (0.329±0.057)/h,T 1/2 ( 2.2±0.4) h; High dose group: Ka (1.934±0.794)/h,t max (1.7±0.3) h,C max ( 749.3±387.2) μg/L,AUC 0-14 (3820.1±1966.4) μg·h/L,Ke (0.373±0.174)/h,T 1/2 ( 2.2±0.7) h. AUC of both erythromycin propionate and erythromycin base was linearly correlated to the doses; T 1/2 was not correlated to the doses, so they followed the first order processes. The pharmacokinetic parameters of erythromycin propionate and erythromycin base had no gender differences. Conclusion The erythromycin stinoprate was absorbed as erythromycin propionate. C max reached at about 1.6 h. T 1/2 of elimination was 2.4～3.1h. The active component of erythromycin propionate was erythromycin. C max of erythromycin is 1.8, T 1/2 is 2.4~3.1h. In the range of oral dose of 250 to 750 mg, both erythromycin propionate and erythromycin base accorded the first order processes. The pharmacokinetic parameters were different with those reported in foreign documents while the gender difference did not exist in Chinese adults.