Meta-Heuristic Approaches for Optimizing Pharmaceutical Inventory Control under Two-Level Trade Credit

The healthcare sector relies on inventory planning to ensure the continuous availability of emergency medications while minimizing wastage and expiry. This study focuses on enhancing the total profitability by jointly optimizing order quantity and replenishment cycle time of the pharmaceutical products. A differential equation is developed to represent time-dependent demand and product expiration, and the resulting cost function of the inventory is transformed into a non-linear minimization problem. Convexity of the model is examined through graphical pairwise analysis of the decision variables. The model considers practical industry factors of the pharmaceutical sector, including the time-sensitive demand, shelf life and trade credit. The optimality of the proposed model is evaluated using conventional and metaheuristic algorithms such as CA, CSA, and RSA. Numerical experiments based on real data on credit period are collected from local and chain pharmacies, demonstrating the applicability of the proposed model. This study offers a framework for pharmaceutical inventory management, providing actionable insights to enhance operational efficiency and profitability while managing time-sensitive healthcare products.