Keywords: 
• theophylline /
• sustained release capsule /
• pharmacokinetics /
• bioequivalence /
• reversed phase high performance liquid chromatography

Abstract: OBJECTIVE To evaluate the bioequivalence assessment of theophylline sustained release capsules in healthy volunteers.METHODSA reversed phase high performance liquid chromatography (RP-HPLC) method was est ablished for the determination of theophylline in plasma after a single oral dose of 200mg domestic theophyline sustained-release capsules and imported theophylline sustained-release capsules in a randomized crossover design.The detector was operated at UV 273nm.RESULTS The dynamic course of theophylline plasma concent rations conformed to a one-compartment open model with a 3P87 program and the main pharmacokinetic parameters after a single oral dose of 200mg domestic sustained-release capsules and imported sust ained-re-lease capsules were as folows C_max were(5.12±0.74)mg/L and(5.14±0.63)mg/L,t_max were(5.4±1.0)h and(5.3±1.1)h,MRT were(17.79±1.48)h and(17.61±1.78)h,t1/2 were(10.55±0.75)h and(10.59±1.10)h,AUC_0-36 were(85.33±10.56)mg·h/L and(86.26±8.80)mg·h/L,respectively.CONCLUSIONS The relative bioavailability of domestic theophylline sustained-release capsules is(98.9±6.4)%.The results of statistical analysis for C_max,AUC_0-36 and AUC_0-∞ showed that domestic sustained-release capsules and imported sustained-release capsules were bioequivalent.