Buprenorphine area under the time concentration curve (AUC) in cats after subcutaneous injection of 0.02 mg/kg (AG6, orange, n = 3), 0.06 mg/kg (AG4, pink, n = 6), 0.12 mg/kg buprenorphine (AG2, 0.3 mg/ml, purple plain, n = 6; AG3, 0.12 mg/ml purple checks, n = 9; AG7, 0.6 mg/ml, purple stripes, n = 3) and 0.24 mg/kg (AG5, black, n = 6)