In this study, an inventory model of pharmaceutical goods that deteriorates or damage to pharmaceutical goods that occurs due to the length of time the goods are stored with a fourth-degree polynomial demand rate is formulated. In the optimal solution, the inventory time at zero (t_1^* ) is 0.478763 and the cycle length (T_1^* ) is 0.698110 with an average minimum total cost ((TC) ̅ ) of $119.…