title: Liposome-encapsulated oxymorphone hydrochloride provides prolonged relief of postsurgical visceral pain in rats.
abstract: Adequate pain control is necessary for optimal postsurgical recovery and humane treatment of laboratory and companion animals. Opioid drugs are currently the most potent analgesic agents available in human and veterinary medicine. Long-acting formulations of opioid drugs confer several important advantages over standard pharmaceutical preparations, especially for use in animals. A long-acting formulation of oxymorphone hydrochloride was produced by encapsulation into liposomes. Liposome-encapsulated (LE) oxymorphone was tested in a rat model of visceral postoperative pain. Rats were given one subcutaneous injection of LE oxymorphone (1.2 or 1.6 mg/kg of body weight) or standard oxymorphone (0.3 mg/kg) at the time of intestinal transection or resection. A single administration of LE oxymorphone hydrochloride was as effective for relief of postoperative pain in rats (P = 0.18), as were multiple (q4 h or q8 h) injections of 0.3 mg/kg of the standard pharmaceutical preparation. The rats given LE oxymorphone prior to intestinal resection also had significantly higher body weight at three and seven days after surgery than did rats that were given standard oxymorphone. In conclusion, LE oxymorphone was effective in treating visceral pain associated with intestinal surgery in rats. On the basis of body weight gain, rats treated with LE oxymorphone had improved recovery outcome, compared with rats treated with repeated injections of standard oxymorphone.
authors.affiliation: Research Animal Resource Center, University of Wisconsin-Madison, 1710 University Ave. Madison, Wisconsin 53705-4098, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Krugner-Higby
authors.forename: Lesley
authors.initials: L
authors.lastname: Smith
authors.forename: Melanee
authors.initials: M
authors.lastname: Clark
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Heath
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Dahly
authors.forename: Beth
authors.initials: B
authors.lastname: Schiffman
authors.forename: Scott
authors.initials: S
authors.lastname: Hubbard-VanStelle
authors.forename: Denise
authors.initials: D
authors.lastname: Ney
authors.forename: Allyson
authors.initials: A
authors.lastname: Wendland
mesh_terms: D015746:Abdominal Pain / Q000209:etiology / Q000517:prevention & control / Q000662:veterinary*; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use*; D000827:Animal Welfare; D000818:Animals; D013505:Digestive System Surgical Procedures / Q000009:adverse effects / Q000662:veterinary*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004337:Drug Carriers; D007279:Injections, Subcutaneous; D008081:Liposomes; D008297:Male; D010111:Oxymorphone / Q000008:administration & dosage / Q000627:therapeutic use*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000209:etiology / Q000517:prevention & control / Q000662:veterinary*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014781:Viscera / Q000503:physiopathology
chemical_list: D000701:Analgesics, Opioid; D004337:Drug Carriers; D008081:Liposomes; D010111:Oxymorphone