RLD in the context of Quality by Design (QbD) refers to the Reference Listed Drug. The provided reference demonstrates its role: during the QbD process to develop a generic drug product, the goal is to create a formulation therapeutically equivalent to the RLD. In this case, generic acetriptan immediate-release (IR) tablets were developed with the aim of matching the properties of the RLD, which is an IR tablet used to alleviate moderate to severe physiological symptoms. Therefore, the RLD serves as the benchmark for the generic drug development process utilizing QbD principles.
