Pharmacokinetics of a novel liquid-gel formulation of diclofenac potassium

DPSGC is a novel liquid formulation of diclofenac potassium encapsulated in a soft gelatin capsule using patented ProSorb^® technology designed to facilitate rapid and consistent gastrointestinal tract absorption. Here we present the pharmacokinetics of DPSGC and Cataflam^® (diclofenac potassium) as assessed in two studies. Study 1 was an open-label, randomized 3-way crossover study design in which 54 healthy fasting subjects received one dose of DPSGC 25 mg (1 x 25 mg), DPSGC 50 mg (2 x 25 mg) or Cataflam 50 mg with a 7-day washout period between doses. Study 2 was an open-label, randomized study in which 53 patients undergoing bunionectomy surgery received Prosorb-D^® 12.5 mg liquid, DPSGC 25 mg, DPSGC 50 mg, or Cataflam 50 mg administered every 8 hours for 7 days. A steady-state pharmacokinetic analysis was performed on Day 4. The Study 1 results for DPSGC 25 mg, DPSGC 50 mg, and Cataflam 50 mg revealed a maximum plasma concentration (C_max) of 1025 ng/mL, 1882 ng/mL, and 1060 ng/mL, respectively; an area under the plasma concentration-time curve (AUC_0-inf) of 582 ng-hr/mL, 1197 ng-hr/mL, and 1111 ng-hr/mL, respectively; and time to maximum plasma concentration (T_max) of 0.45h, 0.48h, and 0.93h, respectively, with coefficients of variation of 28%, 42%, and 92%, respectively. The Study 2 results for Prosorb-D^® 12.5 mg liquid, DPSGC 25 mg, DPSGC 50 mg, and Cataflam 50 mg revealed a steady-state C_max of 302 ng/mL, 749 ng/mL, 1006 ng/mL, and 902 ng/mL, respectively; while the AUC_0-8h were 316 ng-hr/mL, 595 ng-hr/mL, 1029 ng-hr/mL, and 1126 ng-hr/mL, respectively. Diclofenac potassium, using a novel formulation technology, was more rapidly and consistently absorbed versus the reference product, Cataflam, and achieved a similar C_max as Cataflam 50 mg with half the dose. These characteristics are expected to be advantageous in the treatment of mild to moderate pain. —Xanodyne Pharmaceuticals