TY - JOUR ID - Leszczyński2017 LB - Leszczyński2017 AU - Leszczyński, Maciej AU - Ratajczyk, Elżbieta AU - Ledzewicz, Urszula AU - Schättler, Heinz TI - Sufficient conditions for optimality for a mathematical model of drug treatment with pharmacodynamics ST - Sufficient conditions for optimality for a mathematical model of drug treatment with pharmacodynamics JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2017 VL - 37 IS - 3 SP - 403 EP - 419 DO - http://dx.doi.org/10.7494/OpMath.2017.37.3.403 UR - http://dx.doi.org/10.7494/OpMath.2017.37.3.403 AB - We consider an optimal control problem for a general mathematical model of drug treatment with a single agent. The control represents the concentration of the agent and its effect (pharmacodynamics) is modelled by a Hill function (i.e., Michaelis-Menten type kinetics). The aim is to minimize a cost functional consisting of a weighted average related to the state of the system (both at the end and during a fixed therapy horizon) and to the total amount of drugs given. The latter is an indirect measure for the side effects of treatment. It is shown that optimal controls are continuous functions of time that change between full or no dose segments with connecting pieces that take values in the interior of the control set. Sufficient conditions for the strong local optimality of an extremal controlled trajectory in terms of the existence of a solution to a piecewise defined Riccati differential equation are given. KW - optimal control KW - sufficient conditions for optimality KW - method of characteristics KW - pharmacodynamic model SN - 1232-9274 ER -