Significance and UseThis procedure can be used to evaluate formulations containing ingredients intended to inhibit growth of bacteria on intact skin and measures the difference, post-product-exposure, between numbers of bacterial colonies on active test formulation plates and numbers on control plates, expressed as percent inhibition. This procedure may also be used to test for persistence of activity, as a function of time elapsed between application of active test formulation and application of active test plates. Because no procedure for neutralization of the antimicrobial action of active ingredients can be included in the test, the agar patch method is limited to the extent that results expressed as percent inhibition do not differentiate between bacteristatic and bactericidal effects and, hence, must not be portrayed as “reductions.”Scope1.1 This test method determines the antibacterial activity and persistence of test formulations, as measured by the inhibition of a test organism on an agar surface exposed to test sites on human skin treated with the formulations. 1.2 A knowledge of microbiological techniques is required for these procedures. 1.3 It is the responsibility of the investigator to determine if Good Laboratory Practice (GLP) and Good Clinical Practice (GCP) are required and to adhere to these practices, as appropriate. 1.4 In this test method, SI units are used for all applications except linear measure. In that case, inches are used and SI units follow in parentheses. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Performance of this procedure requires the knowledge of regulations pertaining to the protection of human subjects (see 21 CFR, Ch. I, Parts 50 and 56 ).
