https://doi.org/10.1351/goldbook.15223
To be pharmaceutically equivalent, the generic and proprietary formulations must (1) contain the same amount of active ingredient; (2) contain the same active ingredient in the same dosage form; (3) be intended for the same route of administration; and (4) generally be labeled for the same conditions of use.
Note: It is not usually required that the generic and the reference drug contain the same excipients, or that the mechanism by which the active drug substance is released from the formulation be the same. But, the regulation authority approves the generic equivalent on the basis of certain in vitro and in vivo data.
See: bioequivalence, nonproprietary