ASTM_E_1163_-_10_2016.pdf

Designation:E116310(Reapproved 2016)Standard Test Method forEstimating Acute Oral Toxicity in Rats1This standard is issued under the fixed designation E1163;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 lethality(LD50 value,slope and 95%confidence interval(CI)and signs of acutetoxicity from a material using a limited number of rats.Thetechnique used in this test method is referred to as the“Stagewise,Adaptive Dose Method.”2This test method is analternative to the classical LD50 test and is applicable to bothliquids and solids.1.2 This test method is not recommended for test materialswhich typically produce deaths beyond two days postdosing.1.3 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.2.Referenced Documents2.1 ASTM Standards:3E609 Terminology Relating to PesticidesIEEE/ASTM SI 10 Standard for Use of the InternationalSystem of Units(SI)(the Modernized Metric System)3.Terminology3.1 Definitions:3.1.1 delayed deathan animal which does not die orappear moribund within 24 h but dies later during the obser-vation period.3.1.2 gavageforced oral dosing,as by a tube that is passeddown the throat to the stomach.3.1.3 LD50the statistically derived estimate of the dose ofa test substance that would be expected to cause 50%mortalityto the test population under the specified test conditions.3.1.4 moribundat the point of death or extinction.3.1.5 pharmacotoxicgross physiological signs in responseto a toxic material.3.1.6 signs of toxicityobjective,observable evidence oftoxicity.3.1.7 suspensiona mixture in which very small particlesremain suspended without dissolving.3.1.8 toxicitypoisonous quality.4.Summary of Test Method4.1 Three to five different doses of the target compound areselected such that the doses span the entire dose responsecurve,with separation between the doses to be equal logintervals.One to two animals are given each dose as the firststage of the study.After 24 to 48 h,the responses to each doseare observed and used in determining the doses and animalnumbers in the next stage of dosing.4.2 The second and subsequent stages have one to fourdoses with one to three animals at each dose.Doses forsubsequent stages are selected based on the estimates of thedose response distribution parameters and the uncertainties ofthese estimates.The dose response curve and its parameters areupdated after each stage and dosing will stop when the 95%confidence interval for the LD50 satisfies the following stop-ping rule:(upper 95%CI lower 95%CI)/(2 LD50)5 g/kg).12.Calculation of Results12.1 Calculate the dose response curve and its parameters(slope,LD50 and 95%CI)using nonlinear regression on a twoparameter(slope and intercept)probit model after each stageusing the dose,number exposed at the dose,and numberresponding to the dose.As dosing continues with subsequentstages,all stages should be included in the determination of thedose response curve.Therefore,a stage effect should beincluded in the nonlinear regression to determine if responsesdiffer with respect to stage.If stage effects are significant,astage may need to be excluded from the analysis.More specificdetails of the analysis approach are found in Feder.212.1.1 Additional toxicity tests should not be conducted ifthe existing test provides answers to all of the practicalquestions that need to be answered concerning the LD50.12.2 If the maximum number of animals has been used andan adequate LD50 and 95%CI cannot be estimated because thelive and dead animals have no doses in common and all deadanimals have higher doses and all live animals have lowerdoses,then LD50 may approximated by the average betweenthe two doses were live and dead occur.12.3 If the maximum number of animals has been used andan adequate LD50 and 95%CI cannot be estimated because ofthe live and dead animals have no doses in common and alldead animals have higher doses and all live animals have lowerdoses,then LD50 may be approximated by the averagebetween the two doses were live and dead occur.13.Report13.1 The report shall contain such information as testspecies and source and sex of animals.13.2 The report should include study initiation and termi-nation dates,individual body weights,dose levels,doseadministered,return to feeding time,mortality,pharmacotoxicsigns,gross necropsy results,and LD50,if determined.14.Precision and Bias14.1 A precision and bias statement cannot be made at thistime.15.Keywords15.1 chemicals;LD50;oral toxicity;pesticides;ratsASTM International takes no posit