Pharmacokinetics of subcutaneous bupivacaine liposome injectable suspension indicate an extended absorption and elimination profile in swan geese (Anser cygnoid)

This is the authors' abstract. We don't add key points for this paper.

Objective: To determine the pharmacokinetics of a single dose of bupivacaine liposome injectable suspension (BLIS) after SC administration to swan geese (Anser cygnoid). The goal was to assess its potential as an extended-release local anesthetic infiltration in avian patients. It was hypothesized that BLIS at this dose would have low maximal plasma concentrations and a prolonged elimination profile similar to published mammalian data and without adverse effects. Methods: A single dose of BLIS at 5.3 mg/kg was infiltrated SC in 6 adult swan geese (3 males and 3 females). Over the following 96 hours, blood samples were collected at 9 time points for analysis of plasma concentrations of bupivacaine. Concentrations were determined using HPLC-MS and plotted against time for pharmacokinetic analysis via nonlinear modeling. Results: The harmonic mean terminal half-life was 14.8 ± 5.5 hours. The mean maximum concentration was 74 ± 21.9 ng/mL and was achieved in all geese within 8 hours. No adverse effects were noted. Conclusions: These results indicate that BLIS in swan geese has an extended absorption and elimination profile compared to local anesthetics in current use in avian species. Clinical Relevance: Protracted duration of local anesthesia in birds may improve patient care, welfare, and surgical outcomes by allowing a reduction of systemic anesthetic and analgesic doses and reducing the frequency of restraint or isolation needed for treatment.