Critical Quality Attributes |
Hardness
| The hardness of chewable tablets should be such that they withstand the rigors of manufacturing, packaging, shipping, and distribution, as well as be easily chewed by the intended patient population. Hardness is generally measured as the force needed to break the tablet in a specific plane. Tablet hardness may be measured and expressed in a variety of units. Applications submitted to FDA should use the same unit of measure in reporting results and specifications. including: kilopond (kp), kilogram-force (kgf), Newton (N), and Strong-Cobb Units(scu). 1 kp = 93 1 kgf = 9.8 N = 1.4 scu. Public standards also exist to ensure consistent measurement of the tablet hardness (Tablet Breaking Force).
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Disintegration
| The time required for a tablet to break up into small particles is its disintegration time. For chewable tablets, disintegration time should be short enough to prevent GI obstruction in the event a tablet is not completely chewed by the patient. Usually, the presence of the correct type and amount of a disintegrant facilitates rapid disintegration of the tablet. In vitro disintegration testing should be conducted using intact tablets in suitable medium using established disintegration equipment (such as USP Disintegration Apparatus) and methods.
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Dissolution
| Drug absorption from chewable tablets depends on the release of the drug substance(s) from the intact or the chewed tablets; therefore, in vitro dissolution testing of chewable tablets should follow the principles of dissolution testing of conventional IR tablets. That is, the active pharmaceutical ingredient(s) of the chewable tablets should adequately dissolve out of the tablet with or without chewing. For product characterization during development in vitro dissolution testing should be conducted on intact tablets in at least four media, such as water, aqueous media at pH 1.2, buffer pH 4.5, and buffer pH 6.8, with established dissolution methods using equipment such as USP Apparatus 1 (basket), USP Apparatus 2 (paddle), or USP Apparatus 3 (reciprocating cylinder).
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Performance in Simulated Physiological Media
| Chewable tablets should also be evaluated using dissolution media such as simulated fasted and fed state gastric and intestinal fluids with enzymes (biorelevant dissolution media). Hardness should also be tested after brief (30-120 s) exposures to small quantities (1-2 mL) of human or simulated saliva. Such studies may provide a better understanding of in vivo performance of the chewable tablets. In vitro testing in physiological media, consistent with the targeted patient population characteristics may support further characterization of the drug product and its critical quality attributes.
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Biowaiver and Postapproval Considerations
| The solubility and permeability characteristics of the drug substance may be used to determine where the drug fits within the Biopharmaceutics Classification System (BCS). Depending on the BCS classification of the drug substance, proposals for waiver of bioequivalence (BE) studies may be considered for chewable tablets. Changes in the chemistry, manufacturing and controls after approval of the chewable tablets should be made in conformance with the principles outlined in the Scale-up and Post-Approval Changes Immediate Release (SUPAC IR) guidance.
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