In vitro characterization of a formulation of butorphanol tartrate in a poloxamer 407 base intended for use as a parenterally administered slow-release analgesic agent

Delphine Laniesse, Dale A. Smith, Heather K Knych, Cornelia Mosley, David Guzman, Hugues Beaufrère

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

OBJECTIVE To assess rheological properties and in vitro diffusion of poloxamer 407 (P407) and butorphanol–P407 (But-P407) hydrogels and to develop a sustained-release opioid formulation for use in birds. SAMPLE P407 powder and a commercially available injectable butorphanol tartrate formulation (10 mg/mL). PROCEDURES P407 and But-P407 gels were compounded by adding water or butorphanol to P407 powder. Effects of various concentrations of P407 (20%, 25% and 30% [{weight of P407/weight of diluent} X 100]), addition of butorphanol, and sterilization through a microfilter on rheological properties of P407 were measured by use of a rheometer. In vitro diffusion of butorphanol from But-P407 25% through a biological membrane was compared with that of a butorphanol solution. RESULTS P407 20% and 25% formulations were easily compounded, whereas it was difficult to obtain a homogenous P407 30% formulation. The P407 was a gel at avian body temperature, although its viscosity was lower than that at mammalian body temperature. The But-P407 25% formulation (butor-phanol concentration, 8.3 mg/mL) was used for subsequent experiments. Addition of butorphanol to P407 as well as microfiltration did not significantly affect viscosity. Butorphanol diffused in vitro from But-P407, and its diffusion was slower than that from a butorphanol solution. CONCLUSIONS AND CLINICAL RELEVANCE But-P407 25% had in vitro characteristics that would make it a good candidate for use as a sustained-release analgesic medication. Further studies are needed to characterize the pharmacokinetic and pharmacodynamic properties of But-P407 25% in vivo before it can be recommended for use in birds. (Am J Vet Res 2017;78:677–687)

Original languageEnglish (US)
Pages (from-to)677-687
Number of pages11
JournalAmerican Journal of Veterinary Research
Volume78
Issue number6
DOIs
StatePublished - 2017

ASJC Scopus subject areas

  • veterinary(all)

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