Two drug products containing the same active ingredient in the same amounts, dosage forms, and routes of administration are considered pharmaceutical equivalents. Pharmaceutical equivalents are considered bioequivalent if the bioavailability of the active moiety in the drug preparations is comparable. Pharmaceutical equivalents that exhibit bioequivalence are also therapeutically equivalent if, when administered as directed, the drugs possess the same clinical effect and safety profile. For clinical efficacy, the maximum drug concentration and the time required to reach the peak concentration must fall within the acceptable limit. Sometimes, the bioavailability of a drug's dosage form may vary between manufacturers or batches from a single manufacturer. Poor control of differences in various physical characteristics of a drug during formulation and manufacturing influences how the drug disintegrates and dissolves, which affects the drug's bioavailability. If a generic drug is to be approved, its bioequivalence profile must be comparable to the reference product.