Safety study of topical naltrexone therapy for diabetic skin wounds is confirmed in Göttingen mini-pigs

This study was conducted to determine the safety of topical naltrexone treatment in Göttingen swine. Efficacy of topical naltrexone was performed previously in Sprague-Dawley rats. In this study, 25 male and female mini-pigs received topical naltrexone once daily for 30 days. The gel at doses of 1%, 2%, and 10% naltrexone was applied at a dose volume of 0.01 ml/cm² to an area of unbroken skin encompassing 10% of the animal's surface. Body and food consumption, skin and organ morphology, and clinical signs, including blood analyses were taken periodically. Naltrexone levels in serum were measured at the time of death. No adverse observations were made in the cutaneous skin, autopsied organs, or biochemical parameters. The no-observed adverse effect level (NOAEL) was considered to be 2% topical application daily. The conclusions from the veterinarians and researchers are that topical naltrexone at 1% or 2% can be used safely in clinical efficacy studies.