Pharmaceutical equivalence

Bioavailability, Bioequivalence, and Pharmacokinetics. Bioavailabihty can be defined as the amount and rate of absorption of a dmg into the body from an adrninistered dmg product. It is affected by the excipient ingredients in the product, the manufacturing technologies employed, and physical and chemical properties of the dmg itself, eg, particle size and polymorphic form. Two dmg products of the same type, eg, compressed tablets, that contain the same amount of the same dmg are pharmaceutical equivalents, but may have different degrees of bioavailabihty. These are chemical equivalents but are not necessarily bioequivalents. For two pharmaceutically equivalent dmg products to be bioequivalent, they must achieve the same plasma concentration in the same amount of time, ie, have equivalent bioavadabihties. 

For dmgs approved originally between 1938 and 1962, the FDA has utilized the Abbreviated New Dmg AppHcation (ANDA) for review of generic products that are pharmaceutical equivalents of the initially approved products. In this way, costiy dupHcation of animal and human experimentation is avoided. The new manufacturer has to show only that its manufacturing methodology, specifications, quaUty control, and labeling are acceptable. In some cases, the FDA does require proof of bioequivalence. 

Two similar dosage forms, eg, tablets, that contain the same amount of the same dmg entity and meet USP/NF and current good manufacturing practices (FDA) are referred to as pharmaceutical equivalents (PE). When, upon adiriinistration, such tablets achieve similar profiles of AUC, and... 

Another collateral effect of the DESI project was the development of the abbreviated NDA, by which a generic version of the innovator product could satisfy the statutory preconditions for entering the market, without repeating the preclinical and clinical studies of the innovator. This administrative creation, designed to assure that generics were both pharmaceutically equivalent and bioequivalent to the pioneer product, was endorsed by Congress in 1984. As will be seen, this development had a staggering impact on the business model of the pharma industry. 

An NDA can be submitted for a previously unapproved new molecular entity, or for a new salt, new ester, prodrug, or other noncovalent derivative of a previously approved new molecular entity, formulated as a modihed-release drug product. The first modified-release drug product for a previously approved immediate-release drug product should be submitted as an NDA. Subsequent modified-release products that are pharmaceutically equivalent and bioequivalent to the listed drug product should be submitted as ANDAs. BA requirements for the NDA of an extended-release product are listed in 320.25(f). The purpose of an in vivo BA study for which a controlled-release claim is made is to determine if all of the following conditions are met. 

If there is a listed drug that is the pharmaceutical equivalent of the drug proposed in the 505(b)(2) application, the 505(b)(2) applicant should provide patent certifications for the patents listed for the pharmaceutically equivalent drug. Patent certifications should specify the exact patent number(s) and the exact name of the listed drug or other drug even if all relevant patents have expired. 

Two products are bioequivalent in the absence of a significant difference in the rate and extent to which the active ingredient or active moiety in pharmaceutical equivalents or pharmaceutical alternatives becomes available at the site of drug action when administered at the same molar dose under similar conditions in an appropriately designed study [21 CFR 320.1(e)], An appropriately designed comparison could include (1) pharmacokinetic (PK) studies, (2) pharmacodynamic (PD) studies, (3) comparative clinical trials, and/or (4) in vitro studies. 

Pharmaceutical equivalents are those drug products which are formulated to contain the same amount of active ingredient in the same dosage form to meet the same (compendial or other applicable) standards of quality. 

Pharmaceutical alternatives are drug products that contain the same therapeutic moiety, or its precursor, but not necessarily in the same amount or dosage form. Drug products are considered to be therapeutic equivalents only if they are pharmaceutical equivalents and if they can be expected to have the same clinical effect and safety profile when administered to patients under the conditions specified in the labeling. Although pharmaceutical alternatives may ultimately be proven bioequivalent, given their differences they are not automatically presumed to be. 

Given these definitions, FOPs would likely be considered pharmaceutical alternatives if one presumes that pioneer and follow-on proteins are identical at a precursor stage, prior to potential post-translational modification. This presumption may also be consistent with the similarity standard the agency applies to ascertain orphan drug status (see discussion in Section 1.2.6). Follow-on proteins cannot be considered to be therapeutic equivalents since they are not pharmaceutical equivalents and cannot be expected to have the same clinical effect and safety profile in the absence of testing. This assertion is supported by the following ... 

Drug products can be considered to be pharmaceutical equivalents if such products (1) contain the same active ingredients, (2) are of the same dosage form and route of administration, and (3) are identical in strength and concentration. The term therapeutic equivalence is also used to describe pharmaceutical equivalence. Pharmaceutically equivalent drag products may differ in attributes such as shape, color, excipients, and release mechanisms. Pharmaceutical equivalence is of importance in the development of generic drags. See http //www.fda.gov. 

In general, bioequivalence evaluations involve comparisons of dosage forms that are pharmaceutical equivalents. Such dosage forms are defined as drug... 

Bioequivalent drug products are pharmaceutical equivalents whose bioavailability (i.e., rate and extent of systemic drug absorption) does not show a significant difference when administered at the same... 

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