, WI *This article represents the scientific opinion of many experts and, in particular, is derived from a series of workshops held under the auspices of the Federation International Pharmaceutique (FIP) and cosponsored by the Royal Pharmaceutical Society (UK), the Bundesverband der Pharmazeutischen Industrie (BPI), Colloquium Pharmaceuticum (Germany), the American Association of Pharmaceutical Scientists (AAPS, US), and the US Food and Drug Administration. It is

Since its inception, the dissolution test has come under increasing levels of scrutiny regarding its relevance, especially to the correlation of results to levels of drug in blood. The technique is discussed, limited to solid oral dosage forms, beginning with the scientific origins of the dissolution test, followed by a discussion of the roles of dissolution in product development, consistent batch manufacture (QC release), and stability testing. The ultimate role of dissolution testing, "to have the results correlated to in vivo results or in vivo in vitro correlation," is reviewed. The recent debate on mechanical calibration versus performance testing using USP calibrator tablets is presented, followed by a discussion of variability and hydrodynamics of USP Apparatus 1 and Apparatus 2. Finally, the future of dissolution testing is discussed in terms of new initiatives in the industry such as quality by design (QbD), process analytical technology (PAT), and design of experiments (DOE).

Twenty—six species of adult Namib tenebrionid beetles belonging to the tribes Adesmiini and Zophosini have an extracuticular wax bloom covering either part or all of their body surface. These species occur in the dunes, dry river bed, and adjacent gravel plains of the central Namib. The percentage of species possessing a wax bloom increases from the coastal fog desert to the inland hot dry desert. The amount of bloom and its distribution over the integument also increase in a similar manner along the climatic gradient. Despite considerable diversity in coloration and patterns of the wax blooms, the chemical composition of the lipid components showed little variation. Hydrocarbons were the predominant lipid class, with the size of constituent molecules ranging from 19 to 40 carbon atoms. In all species tested, n—alkanes were more abundant than branches alkanes. Odd—numbered carbon chains (e.g., C27, C29, C31) comprised the bulk of the hydrocarbon fractions. The possible functional roles of these blooms in water balance, thermoregulation, predator avoidance, and chemical communication are discussed.

The similarity factor, f2, measures the sameness of dissolution profiles. The following commentary is an overview of discussions and presentations from a group of industry and US regulatory experts that have integrated the science and regulatory research and practice for assessing product performance, particularly for modified-release (MR) dosage forms, using f2. For a drug development sponsor or applicant with an orally complex dosage formulation, it is critical to understand dissolution methods and the similarity factor and how and/or when to apply it in their NDA, ANDA, or PMA submission. As part of any regulatory submission, it is critical to justify that the product performance has not been impacted by any change in the manufacturing process and/or the delayed and/or prolonged drug release characteristics compared to a similar conventional or another orally complex dosage form. The purposes of this document are (1) to provide a description of appropriate dissolution methods, how is the f2 calculated and how it can be used to justify product performance similarity, or not; (2) to provide an overview of alternative methods available for dissolution profile comparisons, and (3) to illustrate how applying these concepts in a focused way supports approval of submissions and regulatory dossiers and aligns them with on-going science and regulatory initiatives. A case study will be used as an example to demonstrate how dissolution testing and the f2 calculation results can impact regulatory outcomes from an NDA (505(b)(1)), NDA (505(b)(2)), ANDA (505(j)), supplemental NDAs/ANDAs, or PMA perspective.

For a dissolution method to be considered relevant to in vivo performance, the dissolution data profiles should show discrimination or meaningful change when there is a change in critical material attributes (CMAs) and critical product properties (CPPs). The dissolution test has been shown repeatedly to have the power to distinguish between significant changes in active pharmaceutical ingredient (API), formulation, and process that relate to the release mechanism of the in vivo performance. Examples will be discussed in the literature where the effects of formulation, drug substance, and manufacturing variables have been measured by dissolution testing. There will be a suggested plan on how to develop and challenge a discriminating method that may be utilized for regulatory purposes. A brief review of other challenges and considerations regarding discriminatory dissolution testing is presented.

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A revision to the general chapters Dissolution <711> and Disintegration and Dissolution of Dietary Supplements <2040> is being proposed to address the shortcomings of the current chapters regarding the use of enzymes in the dissolution test of gelatin capsules or gelatin-coated tablets. The recommendations are to use the enzymes pepsin (medium with pH equal to or below 4.0), papain or bromelain (medium with pH above 4.0 and below 6.8), and pancreatin (medium with pH equal to or above 6.8) if the dosage form does not comply to the appropriate Acceptance Table or, in the case of dietary supplements, appropriate Tolerances requirements due to the presence of cross-linking in the gelatin. Also, the revision clarifies how the enzyme activity should be determined, the amount of enzymes to be added to the medium, and a pre-treatment procedure to be used when the dissolution medium contains surfactant or any other ingredient known or suspect to inactivate the enzyme being used. This Stimuli article provides the rationale for these revisions and presents data to support the recommendations being made. Readers are encouraged to send any comments, questions, suggestions or data to the corresponding author. Also, see the section Other Related Revisions at the end of this article for information on other related general chapters and monographs.

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