Drug dispenser replenishment optimization via mixed integer programming in central fill pharmacy systems

This paper presents a study about drug dispenser replenishment control using mixed integer programming approach to reduce process operation cost in central fill pharmacy systems. Dispensing machine replenishment is one of the critical processes that influences the efficiency in pharmacy automation. The objective of this paper is to find an optimized replenishment strategy through mixed integer programming to minimize total cost, which includes inventory holding cost, shortage cost, device setup cost, and operational cost, considering of demand, resource, and cycle time constraints. Device reorder level is considered in this model, which can suggest an appropriate replenishment reorder time for decision making. The model is tested on two cases and four situations. The influences of different replenishment strategies to system total cost are explored and discussed. The results show that the proposed model can not only give valuable recommendations for replenishment planning, but also boosts the efficiency of the decision making process.