ASTM_E_1882_-_10.pdf

Designation:E188210Standard Test Method forEvaluation of Antimicrobial Formulations by the Agar PatchTechnique1This standard is issued under the fixed designation E1882;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method determines the antibacterial activityand persistence of test formulations,as measured by theinhibition of a test organism on an agar surface exposed to testsites on human skin treated with the formulations.1.2 A knowledge of microbiological techniques is requiredfor these procedures.1.3 It is the responsibility of the investigator to determine ifGood Laboratory Practice(GLP)and Good Clinical Practice(GCP)are required and to adhere to these practices,asappropriate.1.4 In this test method,SI units are used for all applicationsexcept linear measure.In that case,inches are used and SI unitsfollow in parentheses.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Performance of thisprocedure requires the knowledge of regulations pertaining tothe protection of human subjects(see 21 CFR,Ch.I,Parts 50and 56).2.Referenced Documents2.1 Federal Standard221 CFR,Ch.I,Parts 50 and 56 Protection of HumanSubjects3.Terminology3.1 active test formulationa substance containing activeingredient(s).3.2 active ingredienta substance added to a formulationspecifically for the inhibition or inactivation of microorgan-isms.3.3 active plateinoculated agar plate that has been at-tached to a skin site treated with an active formulation.3.4 antibacterial activitykilling of bacteria or supressionof their growth or reproduction.3.5 control formulationa formulation that does not containan active ingredient.3.6 control plateinoculated agar plate that has been at-tached to an untreated skin site,or one treated with a controlformulation.3.7 inhibitionprevention of bacterial population growth,either through lethality or through prevention of bacterialreproduction.3.8 inoculum determination platean inoculated plate thathas not been exposed to any skin test site.3.9 persistenceeffectiveness of a test formulation in inhib-iting bacteria,defined in terms of time elapsed betweenapplication of test formulation and application of test plates.3.10 resident microorganismsmicroorganisms that sur-vive and multiply on the skin,forming a stable population.3.11 transient microorganismsmicroorganisms that con-taminate the skin,but do not form a stable population.3.12 volar aspect of the forearmsthe surface of the fore-arm on the same side as the palm of the hand.4.Summary of Test Method4.1 This test method is conducted on subjects selected froma group of volunteers who have refrained from using topicalantimicrobials for at least one week and have minimal hair onthe test site.The test site should normally have a low numberof resident microorganisms(approximately 104CFU/cm2orfewer)and be easily sampled.4.2 The surfaces of agar contact plates are inoculated withthe selected organism and placed in contact with skin sites thathave been treated with active or control formulations,or leftuntreated.After contact with the treated skin sites,these platesare incubated and the colonies enumerated.Inhibitory activityof the active test formulation is measured by comparing1This test method is under the jurisdiction of ASTM Committee E35 onPesticides,Antimicrobials,and Alternative Control Agents and is the directresponsibility of Subcommittee E35.15 on Antimicrobial Agents.Current edition approved April 1,2010.Published April 2010.Originallyapproved in 1997.Last previous edition approved in 2005 as E1882 05.DOI:10.1520/E1882-10.2Available from Superintendent of Documents,U.S.Government PrintingOffice,Washington,D.C.20402.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 differences in microbial colony counts between plates that werein contact with sites treated with an active formulation andplates that were in contact with untreated sites,or sites treatedwith a control formulation.Results are expressed as percentinhibition.35.Significance and Use5.1 This procedure can be used to evaluate formulationscontaining ingredients intended to inhibit growth of bacteria onintact skin and measures the difference,post-product-exposure,between numbers of bacterial colonies on active test formula-tion plates and numbers on control plates,expressed as percentinhibition.5.2 This procedure may also be used to test for persistenceof activity,as a function of time elapsed between application ofactive test formulation and applic