Typical response-time courses obtained after different doses and routes of administration (3 and 10 µg i.v., and 10, 50, and 100 µg s.c.). Typical response-time courses obtained after different doses and routes of administration (3 and 10 µg i.v., and 10, 50, and 100 µg s.c.). Letters denote the following: A, baseline; B, time delay between expected peak concentration in plasma and observed peak response; C, concave onset of action; D, peak shifts in the response-time courses with increasing doses; E, saturation at top doses; and F, decline of response is slower (absorption rate–limited elimination from biophase) after subcutaneous dosingcompared with intravenously at equal doses. The black bar in the lower-left corner shows the expected peak time of drug in plasma after an intravenous dose or oral solution. See also Table 1 for a suggestion of parameterizations. IV, intraveonous; SC, subcutaneous. Johan Gabrielsson et al. Pharmacol Rev 2019;71:89-122 Copyright © 2018 by The Author(s)‏