Pharmaceutical equivalence by design for generic drugs: modified-release products.

The Office of Generic Drugs has ensured the high quality of generic products based upon two requirements: pharmaceutical equivalence and bioequivalence to the reference listed drug (RLD). This paradigm has been used with success toward ensuring quality generic drug products that provide the same therapeutic benefit as the RLD. Drug products have increased in design complexity; as a result, approaches to ensure therapeutic equivalence must evolve to provide assurance of quality generic drug products.