In vitro effects and in vivo efficacy of a novel cyclooxygenase-2 inhibitor in dogs with experimentally induced synovitis

Am J Vet Res. 2004 Apr;65(4):503-12. doi: 10.2460/ajvr.2004.65.503.

Abstract

Objective: To determine cyclooxygenase-2 (COX-2) selectivity, pharmacokinetic properties, and in vivo efficacy of ML-1,785,713 in dogs.

Animals: 21 healthy male and female mixed-breed dogs and 24 healthy male Beagles.

Procedure: Selectivity of ML-1,785,713 for inhibiting COX-2 was determined by comparing the potency for inhibiting cyclooxygenase-1 (COX-1) with that of COX-2 in canine blood. Pharmacokinetic properties were determined after i.v. (2 mg/kg) and oral (8 mg/kg) administration in female mixed-breed dogs. In vivo efficacy was evaluated in male mixed-breed dogs with urate crystal-induced synovitis. Prophylactic efficacy was evaluated by administering ML-1,785,713 two hours before induction of synovitis whereas therapeutic efficacy was determined by administering ML-1,785,713 one hour after induction of synovitis.

Results: Blood concentrations that resulted in 50% inhibition of COX-1 and COX-2 activity in vitro were 119.1 microM and 0.31 microM, respectively, and selectivity ratio for inhibiting COX-2 relative to COX-1 was 384. ML-1,785,713 had high oral bioavailability (101%), low systemic clearance (77 mL/min/kg), and an elimination half-life of 5.9 hours. ML-1,785,713 was efficacious when administered prophylactically and therapeutically to dogs with urate crystal-induced synovitis.

Conclusions and clinical relevance: ML-1,785,713 is a novel, potent COX-2 inhibitor that is the most selective COX-2 inhibitor described for use in dogs to date. ML-1,785,713 has oral bioavailability and low systemic clearance that is comparable to other non-steroidal anti-inflammatory drugs. It is effective after prophylactic and therapeutic administration in attenuating lameness in dogs with urate crystal-induced synovitis. Drugs that specifically inhibit COX-2 and not COX-1 at therapeutic doses may have an improved tolerability profile, compared with nonselective non-steroidal anti-inflammatory drugs.

Publication types

  • Comparative Study

MeSH terms

  • 4-Butyrolactone / analogs & derivatives
  • 4-Butyrolactone / pharmacokinetics
  • 4-Butyrolactone / therapeutic use*
  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacokinetics
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use*
  • Carbazoles
  • Cyclooxygenase Inhibitors / pharmacokinetics
  • Cyclooxygenase Inhibitors / therapeutic use*
  • Dog Diseases / drug therapy*
  • Dogs
  • Dose-Response Relationship, Drug
  • Sulfonamides
  • Sulfones / pharmacokinetics
  • Sulfones / therapeutic use*
  • Synovitis / drug therapy
  • Synovitis / veterinary*

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Carbazoles
  • Cyclooxygenase Inhibitors
  • Sulfonamides
  • Sulfones
  • carprofen
  • 4-Butyrolactone
  • deracoxib
  • firocoxib