Timing ofthe administration

Stability ofthe article/carrier mixture can be established in conjunction with the homogeneity assays of nonsolutions. Separate stability tests will, of course, be required for solutions. Formal stability trials sufficient to show long-term stability of the mixtures are not required rather, stability should be established for a period that encompasses the period of use of the article/carrier mixture. Period of use should be defined as whichever of the following two time periods is longer, the time between preparation of the mixture and final administration of that mixture to the test system, or the time between preparation of the mixture and the analysis of the mixture as required by 58.113(a)(2). Often the period between preparation and analysis may be longer than the period between preparation and last administration to the test system. 

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