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Published on: September 1, 2016
A pharmacokinetic study of extended-release buprenorphine in cynomolgus monkeys (Macaca fasicularis)
Hilton Klein1, Barry L Levinson2, Steven L Leary2
1International Consultants in Laboratory Animal Medicine, Hilton Head Island, South Carolina, USA.
Background:
A novel buprenorphine (BUP) extended-release formulation (BUP-XR) produced as a lipid-encapsulated, low viscosity BUP suspension for subcutaneous (SC) injection to control pain was evaluated for pharmacokinetics and safety in four adult male cynomolgus monkeys.
Methods:
Each animal was given 0.2 mg/kg reformulated BUP-XR SC. Clinical observations were made during the course of the study. Blood samples were obtained from each animal before BUP-XR administration, 6, 24, 48, 72, and 96 h post-BUP-XR injection. Plasma levels of buprenorphine were analyzed using HPLC-MS/MS. The PK values calculated included peak plasma concentration of the BUP analyte, time to peak plasma concentration, plasma half-life, area under the plasma concentration-time curve, clearance, apparent volume of distribution, and elimination rate constant (Cmax , Tmax , T½ , AUC0-t , CL, Vd, and Ke, respectively).
Results:
Observable adverse clinical signs were not detected. BUP concentration peaked from 6 to 48 h, then declined in a linear fashion. Quantifiable plasma BUP was measured in all monkeys at all time points. Results indicate that a single BUP-XR dose at 0.2 mg/kg can reliably provide plasma levels of BUP reported in the literature to be therapeutically relevant for up to 96 h.
Conclusions:
Because of the lack of any clinical observations or adverse effects at the injection site or absence of observable abnormal behaviors, it may be concluded that the use of BUP-XR is safe and efficacious in this species of non-human primate at the dose regimen described in this study for up to 96 h post-administration.

