Application of Clinical Pharmacology Principles in Drug Development of Modifiedâ€Release Products: Leveraging Exposureâ€Response Information to Support Approval.The development of modifiedâ€release (MR) drug products aims to address a clinical need such as improving patient compliance. There are multiple pathways and development strategies for the registration and approval of MR products. The development strategy of an MR product is usually dependent on the availability and pharmacokinetic/pharmacodynamics (PK/PD) characteristics of the reference drug product, that is, an immediateâ€release (IR) product or a reference MR. Compared with a reference IR product, an MR product is likely to have a different PK profile over the least common dosing time due to unequal dosing intervals.The development of modifiedâ€release (MR) drug products aims to address a clinical need such as improving patient compliance. There are multiple pathways and development strategies for the registration and approval of MR products. The development strategy of an MR product is usually dependent on the availability and pharmacokinetic/pharmacodynamics (PK/PD) characteristics of the reference drug product, that is, an immediateâ€release (IR) product or a reference MR. Compared with a reference IR product, an MR product is likely to have a different PK profile over the least common dosing time due to unequal dosing intervals.