Pharmacokinetics and Bioequivalence of Diclofenac Sodium Sustained-Release Capsules

Two brands of diclofenac sodium sustained-release capsules were orally given to 18 healthy male volunteers to investigate the bioequivalence with single-dose and multiple-dose randomized cross-over designs.The drug concentration in plasma was determined by HPLC.The results showed that tmax,cmax and AUC0-∞ of the test(T) and reference(R) capsules after single oral administration of 100mg were(3.4±0.9) and(3.3±0.9)h,(416.0±183.5) and(466.3±238.2)ng/ml,(1986.3±713.1) and(2137.1±871.0)ng·h·ml-1,respectively.The tmax,cmax and AUCss in the multiple-dose test(100mg/d for 6d) were(3.7±0.9) and(3.6±1.0)h,(322.4±93.5) and(337.8±104.9)ng/ml,(1618.6±424.4) and(1728.1±454.3)ng·h·ml-1,respectively.The relative bioavailability of T capsules in single-dose and multiple-dose tests were(95.6±19.9)% and(94.3±8.1)%.Two capsules were bioequivalent by two one-side t test.