Evaluation of 25% Poloxamer As a Slow Release Carrier for Morphine in a Rat Model

• Published in: Frontiers in veterinary science Vol. 5; p. 19
• Main Authors: Sulimai, Nurul H, Ko, Jeff C, Jones-Hall, Yava L, Weng, Hsin-Yi, Deng, Meng, Breur, Gert J, Knipp, Gregory T
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 09.03.2018
• Subjects: histopathology; morphine; pharmacokinetic; poloxamer; rat; slow release; Veterinary Science; histopathology; poloxamer; rat; pharmacokinetic; morphine; slow release
• ISSN: 2297-1769; 2297-1769
• DOI: 10.3389/fvets.2018.00019

The objectives of this study were to evaluate poloxamer as a slow release carrier for morphine (M) and potential tissue irritation after subcutaneous poloxamer-morphine (PM) injection in a rat model. Based on the result of a previous work, 25% poloxamer, with and without morphine, and saline were administered in 14 rats' flanks. Blood for morphine concentrations was automatically sampled at multiple preprogrammed time points using the Culex™ unit for 48 h. Skin tissues from the injection sites were harvested and evaluated for histopathological changes. Following M or PM administration, it was determined that the half-life ( ) was significantly longer in the PM (5.5 ± 7.2 h) than M (0.7 ± 0.8 h) indicated a slow dissolution of poloxamer with morphine. The was within 15 min and was approximately three times higher with M than with PM, reaching 716.8 (±153.7 ng/ml) of plasma morphine concentrations. There was no significant difference in total area under the curve and clearance of M versus PM. Histology inflammatory scores were similar between M, PM, and poloxamer but were significantly higher than saline control. We concluded that 25% poloxamer was capable of increasing the of morphine, without a significant tissue irritation.