Comparison of different formulations of extended-release buprenorphine in perioperative pain management in common marmosets (Callithrix jacchus) (2025)

Mokhtar Pouriani, K., McAndrew, R., Chan, N. et al.

Abstract

Common marmosets (Callithrix jacchus) are increasingly used in biomedical research and often undergo surgery as part of IACUC-approved protocols. Therefore, pain control is essential to their clinical management and welfare. Extended-release buprenorphine is a valuable opioid analgesic option, as it can maintain plasma concentrations above therapeutic levels (0.1 ng/mL) for at least 72 h. However, no validated model is available to verify the analgesic effect of buprenorphine in marmosets. Therefore, this study compared the effects of buprenorphine-ER-LAB (Bup-ER-LAB) at 0.15 mg/kg and Ethiqa XR (EXR) at 0.15 and 0.1 mg/kg administered subcutaneously in marmosets undergoing surgical oocyte collection (n = 12 females) or vasectomy (n = 9 males). We hypothesized that these doses and formulations would provide similar analgesia during the 72-h postoperative period, determined with a marmoset composite measure pain scale designed for cage-side semiquantitative assessment of postoperative pain. The composite measure pain scale focused on animal appearance, activity, body posture/integument, respiration, surgical site, and social interactions, each with different subcategories and corresponding points to obtain a cumulative score. Animals were also assessed cage-side for locomotor activity and injection site reactions. No to minimal pain was scored, and no marmoset needed rescue analgesia. In total, 56% of the males and 25% of the females showed increased activity, which could last up to 48 h. Increased activity occurred in 57% of the BUP-ER-LAB group, 43% of the EXR 0.15 mg/kg group, and 14% of the EXR 0.1 mg/kg group (3 males and 4 females per group). Injection site reactions (erythema and/or swelling) occurred in 57% of the Bup-ER-LAB group, 29% of the EXR 0.15 mg/kg group, and 14% of the EXR 0.1 mg/kg group. Based on our results, we conclude that these formulations provide similar postoperative analgesia in marmosets, and an EXR dosage between 0.1 to 0.15 mg/kg provides adequate analgesia with less increase in activity and risk for injection site reaction.