Physiologically-based pharmacokinetic (PBPK) model-predicted and observed concentration-time profiles of buprenorphine following intravenous (i.v.) administration. Blue solid line and shaded area represent the mean and 5th to 95th percentile range of the virtual population (n = 100), respectively. Open circles represent individual observations. Closed circles and whiskers represent mean and standard deviation of the observations, respectively. References for reported observations are provided in Table 2.