Pharmacokinetic comparison of an oral diclofenac potassium liquid-filled soft gelatin capsule with a diclofenac potassium tablet

OBJECTIVE: To compare the pharmacokinetic profiles of diclofenac potassium liquid-filled soft gelatin capsules (DPSGC) using patented ProSorb dispersion technology with an immediate-release, diclofenac potassium 50-mg comparator tablet in two open-label, single-dose, randomized, crossover relative bioavailability studies in healthy volunteers. METHODS: In Study 1, volunteers (n = 21) received DPSGC 50 mg or a diclofenac potassium 50-mg comparator tablet in two inpatient study periods. In Study 2 (n = 54), volunteers received DPSGC 25 mg, DPSGC 50 mg, or a diclofenac potassium 50-mg comparator immediate-release tablet in three inpatient study periods. RESULTS: In both studies, DPSGC 50 mg displayed a significantly shorter T(max) and higher C(max) than the 50-mg diclofenac potassium comparator tablet. DPSGC 25 mg (Study 2) produced a shorter T(max) (0.45 h) and an equivalent C(max) (1125 ng/ml) to the 50-mg comparator drug. Plasma diclofenac concentration-time courses for the diclofenac potassium 50-mg comparator tablet showed many low, delayed, or multiple peaks compared with DPSGC treatments. CONCLUSIONS: DPSGC 25 mg and 50 mg were more rapidly and consistently absorbed than diclofenac potassium 50-mg comparator tablets. The C(max) of DPSGC 25 mg was equivalent to the 50-mg diclofenac potassium comparator tablet. These characteristics may be beneficial when fast, consistent drug absorption is needed.