GPO Box 58, Sydney NSW 2001, Australia

Existing Chemical HazardAssessment Report

DiisoheptylPhthalateJune 2008

NATIONALINDUSTRIALCHEMICALSNOTIFICATIONANDASSESSMENTSCHEME

GPO Box 58, Sydney NSW 2001, Australia

©CommonwealthofAustralia2008

Thisworkiscopyright.Youmaydownload,display,printandreproducethismaterialinunalteredformonly(retainingthisnotice)foryourpersonal,non-commercialuseorusewithinyourorganisation.ApartfromanyuseaspermittedundertheCopyrightAct1968,allotherrightsarereserved.RequestsandinquiriesconcerningreproductionandrightsshouldbeaddressedtoCommonwealthCopyrightAdministration,AttorneyGeneral’sDepartment,RobertGarranOffices,NationalCircuit,BartonACT2600orpostedat

Preface

ThisreportwascompiledundertheNationalIndustrialChemicalsNotificationandAssessmentScheme(NICNAS).ThisSchemewasestablishedbytheIndustrialChemicals(NotificationandAssessment)Act1989(Cwlth)(theAct),whichcameintooperationon17July1990.

Theprincipal aimof NICNAS isto aid inthe protection of peopleat work, the public and theenvironmentfromtheharmfuleffectsofindustrialchemicals.

NICNASassessmentsarecarriedoutinconjunctionwiththeDepartmentofEnvironmentandHeritage,whichcarryouttheenvironmentalassessmentforNICNAS.NICNAShastwomajorprograms:theassessmentofthehealthandenvironmentaleffectsofnewindustrialchemicalspriortoimportationormanufacture;andtheotherfocussingontheassessmentofchemicalsalreadyinuseinAustraliainresponsetospecificconcernsabouttheirhealth/orenvironmentaleffects.

ThereisanestablishedmechanismwithinNICNASforprioritisingandassessingthemanythousandsofexistingchemicalsinuseinAustralia.

ForthepurposesofSection78(1)oftheAct,copiesofassessmentreportsforNewandExistingChemical assessmentsare freelyavailable fromthe web(CommonwealthChemicalGazette(

CopiesofthisreportandotherNICNASreportsareavailableontheNICNASwebsite.HardcopiesareavailablefromNICNASatthefollowingaddress:

GPOBox58

SydneyNSW2001AUSTRALIA

Attention:OfficeManagerTel:+61(02)85778800

Freecall:1800638528

Fax:+61(02)85778888

Email:

OtherinformationaboutNICNAS(alsoavailableonrequest)includes:

•NICNASAnnualReports.

•NICNASServiceCharter.

•BrochureonNICNASRegistration.

MoreinformationonNICNAScanbefoundattheNICNASwebsite:

Overview

Thisreviewofdiisoheptylphthalate(DiHepP)isahealthhazardassessmentonly.Forthisassessment,theOrganisationforEconomicCooperationandDevelopment,ScreeningInformationDataSet(OECDSIDS)InitialAssessmentReportonDiHepPwasconsulted.InformationfromthisreportwassupplementedwithliteraturesurveysconducteduptoSeptember2006.

DiHepPproductionvolumeisbetween20000and200000tonnesperannumworldwide,withoneproductionsiteinEuropeandoneintheUSA.DiHepPisprincipallyusedwithpolymersasanadditivetoimpartflexibilityinpolyvinylchloride(PVC)resins.PVC-containingphthalateesterapplicationsincludeflooringandwallcoverings.Polymerscontainingphthalateesterapplicationsthatarenon-PVCbasedincludecelluloseplastics,rubbersandselectedpaintsandadhesives.

InAustralia,DiHepPisimportedforuseasaspecialistPVCplasticiserandinscreenprintinginks.

Structurally,phthalateestersarecharacterizedbyadiesterstructureconsistingofabenzenedicarboxylicacidheadgrouplinkedtotwoestersidechains.DiHepPpossesses2branchedesterside chains each withabackboneofpredominantly 6carbons(C6).DiHepP isconsideredtobelongtoagroupof‘transitional’phthalatesdefinedasthoseproducedfromalcoholswithstraight-chaincarbonbackbonesofC4-6.

ToxicitydataforDiHepPwerenotavailableforallhealthendpoints.Forendpointswithmissingorincompletedata,informationfromstructurallysimilarphthalates,whereavailable,wasusedtoextrapolatepotentialtoxicity.Relevantread-acrossinformationwasobtainedfromotherNICNAShazardassessmentreportsforphthalatesandtheNICNASPhthalatesHazardCompendium,whichcontainsacomparativeanalysisoftoxicityendpointsacross24ortho-phthalates,includingDiHepP.

NotoxicokineticdatawereavailableforDiHepP.Basedonthetoxicokineticprofileofphthalatesingeneral,DiHepPislikelytoberapidlyabsorbedasthemonoesterfromthegutandexcretedviatheurine.

DiHepPhaslowacuteoralanddermaltoxicity.Itcausedminimalskinandeyeirritanteffectsinrabbits,anddidnotinduceanyskinsensitisationinguineapigsorhumans.

NorepeatdosetoxicitystudieswereavailableforDiHepP.Inreproductivetoxicitystudies,effectsintheliver,kidneyandpituitarywereseen,withhistopathologyreportedinallthreeorgans.Livereffects,namely hepatocyteenlargement,wereconsistentwithrepeatdoseeffectsseenwithothertransitionalphthalates.ArepeatdoseoralNOAELofapproximately50-168mg/kgbw/d(m-f)wasdeterminedforratsinthesestudies,withaLOAELof222-750mg/kgbw/d(m-f)basedonliverandkidneychanges.

DiHepPwasnotmutagenicinbacterialmutationandcytogenetictest.Noinvitromammalianmutationand invivo genotoxicitydatawereavailableforDiHepP.Overall,resultsofin vitrotestsindicatethatDiHepPisnon-genotoxic.

InvivostudiesinratsandmiceundertakentoinvestigatetheeffectsofDiHepPonmechanismsassociatedwithhepaticcarcinogenicityfoundthatDiHepPhadnoinhibitory

effectongapjunctionalintercellularcommunication(GJIC).HoweversignificantelevationsinhepaticDNAsynthesiswereseeninbothspecies.

NoadequatecarcinogenicitydataareavailableforDiHepP.Duetoinsufficienttestingonotherphthalates,itisnotpossibletoextrapolatecarcinogenicpotentialforDiHepP.

Inatwo-generationstudy,effectsonfertility(decreasedreproductiveperformanceandfertilityindex)wereseeninbothsexesintheF1generationatthehighestdoselevel8000ppm(approximately830mg/kgbw/dpriortobreedingand540mg/kgbw/dduringgestation).TheNOAELforreproductiveeffectsinmalesandfemaleswas4500ppm(227-750mg/kgbw/d)andtheLOAELwas8000ppm(419-1360mg/kgbw/d)intheF1generationbasedondecreasedreproductiveorganweight.

Developmentaleffectsseeninthetwo-generationstudyoccurredmainlywiththe4500and8000ppmgroupsinF1andF2generations,respectively.ThematernalanddevelopmentalNOAELwas1000ppm(50-168mg/kgbw/d),andtheLOAELwas4500ppm(222-750mg/kgbw/d)basedondecreasedanogenitaldistance(AGD)intheF2maleoffspring.

Inanotherdevelopmentalstudy,overtdevelopmentaleffectswereseenat750mg/kgbw/d,whichincludedanincreaseinresorptions(perlitterandperimplantationsite)andarelateddecreaseinlivefoetusesandanincreasedincidenceoffoetuseswithexternal,visceralandskeletalmalformationscomparedtocontrols.ThedevelopmentalNOAELwasestablishedat300mg/kgbw/d,withaLOAELof750mg/kgbw/dbasedonincreasedresorptionsandmalformations.

DiHepPdidnotexhibitanyoestrogenicactivitywhentestedinmostinvitroandinvivoassayswithonlyanisomericmixturedemonstratingweakoestrogenicactivitiesinahumanoestrogenreceptora(ERa)(butnotERb)reportergeneassay.

AcronymsandAbbreviations

erviceary

decyl)phthalate

on)ration)

ellularcommunicationtice

ntration

erse-effectlevel

hemicalsNotificationandAssessmentScheme

-effectlevel

OECDOrganisationforEconomicCooperationandDevelopmentPBOXperoxisomalbeta-oxidationactivity

ppmpartspermillion

PVCpolyvinylchloride

w/wweightperweight

μmicro

1.Introduction

Thisreviewofdiisoheptylphthalate(DiHepP)isahealthhazardassessmentonly.Forthisassessment,anOECDSIDSInitialAssessmentReportonDiisoheptylPhthalate(OECD,2005)wasconsulted.Informationfromthisreportwassupplemented withrelevant studiesfrommore recent literaturesurveysconducteduptoSeptember2006.

Information onAustralianuseswascompiledfromdata suppliedbyindustryin 2004and2006.

Referencesnotmarkedwithanasteriskwereexaminedforthepurposesofthisassessment.Referencesnotexaminedbutquotedfromthekeyreportassecondarycitationsarealsonotedinthisassessmentandmarkedwithanasterisk.

Hazardinformationfromthisassessmentispublishedalsointheformofahazardcompendiumprovidingacomparativeanalysisofkeytoxicityendpointsfor24ortho-phthalates(NICNAS,2008).

2.Identity

2.1Identification of the substance

CASNumber(s):71888-89-6

Note:DiHepPastheC7isomeraloneisknownbyCASnumber41451-28-9

ChemicalName:1,2-Benzenedicarboxylicacid,di-C6-8-branchedalkylesters,C7rich

CommonName:Diisoheptylphthalate(DiHepP)

MolecularFormula:C22H34O4 StructuralFormula:

DiHepPconsistsofatleast80%ofmethylhexylphthalate.ThereforethelinearbackboneispredominantlyC6.ThemethylgroupbranchingcanbefoundondifferentCpositionsofthehexylbackbonechain.

MolecularWeight:363(basedondi-C7H15alkylester)Synonyms:DIHP;Diisoheptylphthalateester;1,2-

Benzenedicarboxylicacid,diisoheptylester

Purity/Impurities/Additives:Purity:>99.9%w/w

Impurities:≤0.1%w/w,includingisoheptylalcohol(0.03%),diisoheptyletherandisoheptylbenzoate(0.07%)

Additives:none

2.2Physicochemical properties

PropertyValue

PhysicalstateLiquid

Meltingpoint-45°C

Boiling point398°C(101.3kPa)

Density994kg/m3(20°C)

Vapourpressure9.33x10-8kPa(25°C)

Watersolubility1.7x10-5g/L(22°C)Partitioncoefficientn-octanol/water(logKow) 6.87

Henry’slaw constant1.99Pa-m3/mole(25°C)

FlashpointNotavailable

Source:OECD (2005). Allvalues are calculatedexceptrelative density and water solubility.

3.Uses

In Australia,DiHepP is imported foruse asaspecialist PVCplasticiserandin screenprintinginks.

4.HumanHealthHazard

4.1Toxicokinetics

Previous evaluations

Nodata.

Data not reportedin previous evaluations

Nodata.

Conclusion

Notoxicokineticstudieswereavailableforassessment.

4.2Acute toxicity

Previous evaluations

Laboratories,1979*Laboratories,1979*

Data not reported in previous evaluations

Nodata.

Conclusion

DiHepPhaslowacuteoralanddermaltoxicityinlaboratoryanimals.NoacutetoxicitydatafrominhalationexposureorhumanstudieswereavailableforDiHepP.

4.3Irritation

4.3.1Skin irritation

Previous evaluations

Asingle24-happlicationofDiHepPtoabradedrabbitskin,underoccludedconditions,producedveryslighterythemain3of4animals.Nosignsofoedemawereobserved(MBResearchLaboratories,1979*).

InpreparationforskinsensitisationtestinginaHumanRepeatedInsultPatchTest(HRIPT),15subjectswereexposedtoagroupofC6toC13phthalates,includingDiHepP.Undilutedtestsubstanceswereappliedtotheskinunderanoccludedpatchfor24hoursandreadingsweretakenat30minand24hafterpatchremoval.NosignificantirritationwasnotedfromDiHepP(Medeirosetal.,1999).

Data not reported in previous evaluations

Nodata.

Conclusion

DiHepPcausedminimalskinirritationinrabbitsandhumans.

4.3.2Eye irritation

Previous evaluations

InamodifiedDraizetest,DiHepPwasamildirritant,withamaximum totalscoreof10observedat1h(Draizescaleof0-110).Meanscoresat24,48,and72hoursforthevariousindiceswere0.50,0.50,and0.17,respectivelyforconjunctivalredness;0.33,0.00,and0.00,respectivelyforchemosis;0.67,0.50,and0.00,respectivelyfordischarge;noiridialorcornealeffectswerenoted(MBResearchLaboratories,1979*).

Data not reported in previous evaluations

Nodata.

Conclusion

DiHepPcausedminimaleyeirritationinrabbits.

4.4Sensitisation Previous evaluations

SkinsensitisationstudieshavebeenconductedinguineapigsusingtheMagnusson-

KligmanandBuehlertestmethods.IntheMagnusson-Kligmantest,aweaksensitisationresponsewasobservedforDiHepPinguineapigsduringthere-challengephase,butnotinthechallengephase(ExxonBiomedicalSciences,1991*).IntheBuehlertest,noindicationofasensitisationresponsewasseeninguineapigs(HuntingdonResearchCentre,1994*).

AHumanRepeatedInsultPatchTest(HRIPT)wasconductedina104peopleexposedtoagroupofC6toC13phthalatesusingthemodifiedDraizeprocedure.UndilutedtestsubstancesincludingDiHepPwereindividuallyappliedtotheskin3timesperweekfor3successiveweeksduringtheinductionandchallengephases.NoevidenceofskinsensitisationwasnotedfromexposuretoDiHepP(Medeirosetal.,1999).

Data not reported in previous evaluations

Nodata.

Conclusion

DiHepPdidnotinduceskinsensitisationinguineapigsorinhumans.

4.5Repeated dose toxicity Previous evaluations

Norepeatdose(oral)toxicitystudieshavebeenconductedonDiHepP,apartfrom

reproductivetoxicitystudies,asreportedbelowandindetailinSection4.8.

In adevelopmentaltoxicitystudy(14days gavagedosing atdoses of0,100,300and750mg/kgbw/d)usingSprague-Dawleydams,theonlydatareportedfornon-reproductiveeffectsweredose-relatedincreasesinmeanabsoluteandrelativematernalliverweights,whichwerestatisticallysignificantinthe750mg/kgbw/dgroups.TheLOAELformaternaleffectsinthisstudywasdeterminedas750mg/kgbw/dDiHepP(ExxonBiomedicalSciencesInc.,1997*;McKeeetal.,2006).

Inatwo-generationreproductiontoxicity(dietary)studyinSprague-Dawleyrats(30/sex/dose,dosesof0,1000,4500and8000ppm),dose-relatedincreasesinliverandkidneyweightswereseeninbothsexesofparentalF0andF1animalsat4500ppm(222-750mg/kg/d)and8000ppm(404-1360mg/kg/d)andincreasedpituitaryweights(F1malesat8000ppm).F0animalsweredosedforapproximately90days(ie70dayspriortomating).Histopathologicalfindingsinliver,kidneyandpituitaryincludedcentrilobularhepatocellularhypertrophyandvacuolation,dilatedrenalpelves/hydronephrosisandforF1animals,hypertrophyoftheparsdistalisofthepituitarygland.TheNOAELforsystemictoxicityinF0andF1animalswasdeterminedas1000ppminthediet(approximately50-168mg/kg/d,m-f),withaLOAELof4500ppm(222-750mg/kg/d,m-f)basedonliverandkidneyeffects(WilResearchLaboratoriesInc.,2003*;McKeeetal.,2006).

Smithetal.(2000)reportedthatratsandmicefeddietscontainingDiHepP(0,1000,12000mg/kginrats;0,500,6000mg/kginmice,for2and4weeks)producedeffectsindicativeofperoxisomeproliferation.ThisincludedincreasedperiportalDNAsynthesisandelevatedperoxisomalbeta-oxidation(PBOX)intheliverofbothF344ratsandB6C3F1mice,alongwithincreasedliverweights(F344speciesonly).

Data not reported in previous evaluations

Nodata.

Conclusion

Inrats,theliverandkidneyweretheprimarytargetorgans,withincreasedorganweightsandhistologicaleffectsobservedintheseorgansandtoalesserextentinthepituitary.Hepatocellularhypertrophyandvacuolationintheliverwerelikelyassociatedwithperoxisomeproliferation.TherepeatdosesubchronicoralNOAELinratswas50-168mg/kgbw/d(m-f)withaLOAELof222-750mg/kgbw/d(m-f)basedonliverandkidneyeffects.

4.6Genetic toxicity

Previous evaluations

DiHepPwasnotmutagenicinS.typhimurium(TA98,100,1535,1537,1538)reversemutationassays,atconcentrationsupto5000mg/mL,withandwithoutS9metabolicactivation(ExxonBiomedicalSciencesInc.,1995*).

DiHepPdidnotinducechromosomalaberrationsinChinesehamsterovary(CHO)cellsatconcentrationsupto4990mg/mL(HazletonLaboratoriesAmericaInc.,1991*).

Data not reported in previous evaluations

Nodata.

Conclusion

DiHepPwasnegativeinbacterialmutationandinvitrochromosomalaberrationtests.NoinvitromammalianmutationandinvivogenotoxicitydatawereavailableforDiHepP.

4.7Carcinogenicity

Previous evaluations

Noinvivocarcinogenicitystudieswereavailableforassessment.Smithetal.(2000)investigatedtheeffectsofDiHepPonanumberofmechanismsassociatedwithhepatocarcinogenicityinmaleF344ratsandmaleB6C3F1mice.DiHepPatdietarydosesup to12000ppminratsandupto6000ppminmice(forupto4weeks)hadnoinhibitoryeffect on gap junctionalintercellular communication (GJIC) ineitherspecies.HoweversignificantelevationofperiportalDNAsynthesiswasseeninbothspecies,after2weeksdosingof1000ppm(rats)and500ppm(mice).

Data not reported in previous evaluations

Nodata.

Conclusion

NoinvivocarcinogenicitydatawereavailableforDiHepP.

4.8Reproductive toxicity

Traditionalhazardassessmentsconsiderreproductivetoxicityseparatefromdevelopmentaltoxicity.Reproductivetoxicityistestedbyexposingsexuallymatureadultstoachemicalandexaminingtheeffectsontheanimalcapacitytoreproduce.Developmental toxicityisstudied byexposingpregnant damsand lookingfor effectsinthefoetuses.However,thesetestsgenerallydonotdetectchemicalsthatinduceeffectsthatonlyappearpostnatally.Thus,chemicalsthataffectthedevelopingreproductivesystemfollowingprenatalexposuremayalsoaffectsexualmaturationorfunctionalreproductivedisordersthatareonlyapparentatmaturity.Developmentaltoxicitycanthereforeleadtoreproductivetoxicityandthetwoendpointscannotbeclearlydistinguished.

Inthishazardassessment,datawillbepresentedonthebasisoftestprocedure,includingtwo-generationstudies,developmental/prenataltoxicitystudies(onlythedamisdosed,studyendsbeforeparturition)anddevelopmental/postnatalstudies(damisdosedduringgestationandallowedtolitter,studyendsduringweaning).Theeffectsonfertilityanddevelopmentwillthenbediscussedseparatelyintheconclusion.

4.8.1One/two-generation reproduction toxicity studies Previous evaluations

In a dietary two-generation reproductive toxicity study in Sprague-Dawley rats

(30/sex/dose),DiHepPwas administered (toboth sexes)at concentrationsof0, 1000,4500,or8000ppm(inthediet)(WilResearchLaboratoriesInc.,2003*;McKeeetal.,2006).F0andF1animalsreceivedthedietfor70dayspriortomating,throughthematingperiodanduntilthescheduledterminationperiodforadults.DuetoDiHepPbeingadministeredinthediet,thedailydosesweresignificantlydifferentatdifferentlifestages.TheeffectsofDiHepPonallreproductivecapabilitieswereevaluated(includinggonadalfunction,oestrouscyclicity,matingbehaviour,conception,gestation,parturition,andlactationin theF0and F1parentalgenerations).TheF1andF2offspring(pups)wereevaluatedforneonatalsurvival,growthanddevelopment.

Parentaltoxicity(bothF0andF1animals)wasseenat4500and8000ppm,withdose-related increases inliver andkidneyweights andincreased pituitaryweights(inF1malesat8000ppm).TherewasnodifferenceinF0bodyweightduringtreatmentandnodifferenceinspermparametersbetweencontrolandtreatedrats.TheF1littersizewassimilarincontrolandtreatedanimals.

Reproductiveeffectsincludeddecreasedmaleandfemalereproductiveperformance(mating)andfertilityforbothsexesintheF1generationat8000ppm.However,themeanF2littersizewasnodifferentthancontrols.Thisdoseequatedtoapproximately830mg/kgbw/dpriortobreedingand540mg/kgbw/dduringgestation.DecreasedspermproductionratesandreducedtesticularspermconcentrationswereseeninF1malesatalldoselevelsbuttherewerenodifferencesinF1testicularweightsandnopathologicalevidenceofaspermiaortesticularatrophywasseenineitherthelowormiddosegroups.TestesandovaryweightaswellasmaleaccessoryorganweightswerereducedinhighdoseF1offspring.Seminiferoustubuledegenerationwasprevalentinhighdosegroupaswellasepididymalhypospermia.Therewerenotreatment-relatedeffectsonthepercentagesofmotileandprogressivelymotilespermorabsolutenumberandpercentagesofmorphologicallynormalspermatanydoselevel.

Inthisstudy,significantlyreducedoffspringbodyweights(andweightgains)werenotedinF1pupsat8000ppmandF2pupsat4500and8000ppm.Otherdevelopmentaleffectsreportedinthisstudyweredecreasedgonad,kidney,andpituitaryweightsintheF1generation(bothsexes)anddecreasedsecondarysexorganweightsforF1andF2offspring(males)at8000ppm;reducedanogenitaldistance(absoluteandrelative)anddelaysinbalanopreputialseparationinF1pupsat8000ppm;reducedanogenitaldistance(absoluteandrelative)at4500ppmandaboveintheF2generation;hypospadia,swellingoftheprepuce,undescendedtestesandretentionofthoracicnipplesinF1malesat8000ppm.Thehighdose(8000ppmindiet)equatedtoapproximately540mg/kgbw/dduringgestationand1360mg/kgbw/dduringlactation.TheNOAELforsystemictoxicityintheF0andF1generationswas1000ppm(approximately 50-168mg/kgbw/dformalesandfemalesrespectively),withaLOAELof4500ppm(222-750mg/kgbw/d),basedonhistopathologicalfindingsinliverandkidney.TheNOAELforeffectsonfertilitywas4500ppm(227-750mg/kgbw/d)andtheLOAELwas8000ppm(419-1360mg/kgbw/d)intheF1generationbasedondecreasedreproductiveorganweight.TheNOAELfordevelopmentaleffectsandforparentalsystemictoxicitywas1000ppm

(approximately50-168mg/kgbw/dformalesandfemalesrespectively).TheLOAELwas4500ppm(222-750mg/kgbw/d)basedondecreasedanogenitaldistanceintheF2maleoffspring.

4.8.2Prenatal developmentaltoxicitystudies Previous evaluations

A developmental toxicity study was conducted on DiHepP in Sprague-Dawley

femaleratsusingoralgavageatdosesof0,100,300,and750mg/kgbw/dongestationdays6-20(ExxonBiomedicalSciencesInc.,1997*;McKeeetal.,2006).Overtmaternaltoxicitywasnotevident,althoughtherewasanincreaseinliverweightsatandabove300mg/kgbw/d.Developmentaleffectswereseenonlyinthehighdosegroup,whichincludedanincreaseinresorptions(perlitterandperimplantationsite),decreaseinlivefoetuses(increasedembryo/foetaldeath)anddecreasedpupweight.Inaddition,therewasanincreasedincidenceoffoetalmalformationsandvariations,includinganophthalmia,microphthalmia,ectopictestis/ovaries,abnormaloriginoragenesisofthebloodvessels,andagenesis,misshapen,fusedormalformedbonesoftheskullsternebrae,ribsorvertebrae,withstuntedfoetusesinapproximatelyhalfofthelitters,comparedtocontrols.Inthisstudy,thedevelopmentalNOAELwasestablishedat300mg/kgbw/d,withaLOAELof750mg/kgbw/dbasedonincreasedresorptionsandmalformations.

Data not reported in previous evaluations

Nodata.

4.8.3Mode of action

DiHepP(upto2000mg/kg)didnotinduceoestrogenicresponsesinvivoinuterotrophicandvaginalcornificationassaysusingimmatureandmatureovariectomisedrats(Zacharewskietal.,1998).DiHepP(unknownisomer)wasnegativeforoestrogenicactivityinayeasttwo-hybridassay(Nishiharaetal.,2000).DBPwasnotacompetitiveagonistattheoestrogenreceptorinaninvitrocompetitiveligand-bindingassayanddidnotinduceoestrogenreceptor-mediatedgeneexpressioninMCF-7cells(Zacharewskietal.,1998).DiHepP(isomericmixture)demonstratedweakoestrogenicactivitiesinahumanoestrogenreceptor(ER)α(butnotβ)reportergeneassayinCHO-K1cellstransfectedwithexpressionvectorsforERα,ERβandandrogenreceptor(AR)(Takeuchietal.,2005).However,DiHepP(upto10-5M)hadnobindingaffinityfortheERαorERβinvitro(Todaetal.,2004).DiHepPdemonstratedanti-oestrogenicandanti-androgenicactivityinthehERβ-andhAR-transactivationassays,respectively(Takeuchietal.,2005).

Conclusion

Effectsonfertility

Reproductiveeffectsreportedinatwo-generationreproductivetoxicitystudyweremainlyatthehighdose(8000ppm)andatorabovethesystemictoxicdose(4500ppm).Decreasedspermproductionratesandreducedtesticularsperm concentrationsseenatandabove1000ppm(inF1males)wasconsideredtobeanexperimentalartefactratherthanatreatment-relatedeffect,asnodifferenceswereseeninF1testicular weights and no pathologicalevidence of aspermia ortesticular atrophywas

seenineitherthelowor middosegroups(OECD,2005).Alsotherewerenotreatment-relatedeffectsonspermmotilityorpercentagesof morphologicallynormalspermatanydoselevel.TheNOAELforparentalsystemictoxicityintheF0andF1generationswas1000ppminthediet(50-168mg/kgbw/d,m-f),withaLOAELof4500ppm(222-750mg/kgbw/d,m-f),basedonliverandkidneyeffects.TheNOAELforreproductiveeffectsinmalesandfemaleswas4500ppm(227-750mg/kgbw/d)andtheLOAELwas8000ppm(419-1360mg/kgbw/d)intheF1generationbasedondecreasedreproductiveorganweight.

Developmental effects

Developmentaleffectsseeninthetwo-generationstudyoccurredeitheratorabovematernallytoxicdoselevels.ThematernalanddevelopmentalNOAELwas1000ppm(50-168mg/kgbw/d),andtheLOAELwas4500ppm(222-750mg/kgbw/d)basedondecreasedanogenitaldistanceintheF2maleoffspring.Inadevelopmentalstudy,overtdevelopmentaleffectswereseenat750mg/kgbw/d.Increasedmaternalliverweightwasobservedatandabove300mg/kgbw/d.ThedevelopmentalNOAELwasestablishedat300mg/kgbw/d,withaLOAELof750mg/kgbw/dbasedonincreasedresorptionsandmalformations.

5.HazardCharacterisation

ToxicitydataforDiHepPwerenotavailableforallhealthendpoints.Forendpointswithmissingorincompletedata,informationfromstructurallysimilarphthalates,whereavailable,wasusedtoextrapolatepotentialtoxicity.Relevantread-acrossinformationwasobtainedfromotherNICNASassessmentreportsforrelevantphthalatesandtheNICNASPhthalatesHazardCompendium(NICNAS,2008)whichcontainsacomparativeanalysisoftoxicityendpointsacross24ortho-phthalates,includingDiHepP.

DiHepPhas an alkylcarbon backbone ofC6-8andisconsidered tobelongtoa groupof“transitional”phthalatesdefinedasthoseproducedfromalcoholswithstraight-chaincarbonbackbonesofC4-6(NICNAS,2008).

NotoxicokineticdataareavailableforDiHepP.Basedonthetoxicokineticprofileofphthalatesingeneral,DiHepPislikelytoberapidlyabsorbedasthemonoesterfromthegutandexcretedviatheurine.

DiHepPhaslowacuteoralanddermaltoxicity.Itcausesminimalskinandeyeirritanteffectsinrabbits,anddidnotinduceanyskinsensitisationinguineapigsorhumans.

NorepeatdosetoxicitydataareavailableforDiHepP,apartfromreproductivetoxicity studies.Effectswereseenin thesestudieson liver,kidneyandpituitary,withhistopathologyreportedinallthreeorgans.Effectsontheliver,namelyhepatocyteenlargement,wereconsistentwithrepeatdosestudieswithothertransitionalphthalates.ArepeatdoseoralNOAELofapproximately50-168mg/kgbw/d(m-f)wasdeterminedforratsinthesestudies,withaLOAELof222-750mg/kgbw/d(m-f)basedonliverandkidneyeffects.

DiHepPwasnotmutagenicwhentestedindifferentstrainsofS.typhimuriumwithandwithoutmetabolicactivationanddidnotinducestructuralchromosomeaberrationsinCHOcells,withoutmetabolicactivation.NoinvitromammalianmutationandinvivogenotoxicitydataareavailableforDiHepP.Overall,resultsofin vitro (bacterialmutationandcytogenetic) testsindicate thatDiHepPis non-genotoxic.

InvivostudiesinratsandmiceundertakentoinvestigatetheeffectsofDiHepPonmechanismsassociatedwithhepaticcarcinogenicityfoundthatDiHepPhadnoinhibitoryeffectongapjunctionalintercellularcommunication(GJIC).HoweversignificantelevationsinhepaticDNAsynthesiswereseeninbothspecies.

Noadequate carcinogenicitydata are available for DiHepP. Due to insufficienttestingonotherphthalates,itisnotpossibletoextrapolatecarcinogenicpotentialforDiHepP.

Inatwo-generationstudy,effectsonfertility(decreasedreproductiveperformanceandfertilityindex)wereseeninbothsexesintheF1generationatthehighestdoselevel8000ppm(approximately830mg/kgbw/dpriortobreedingand540mg/kgbw/dduringgestation).DecreasedmeanspermproductionratesanddecreasedtesticularspermconcentrationswereobservedinF1malesatalldoses,butthisfindingmayhavebeenanexperimentalartefactratherthanatreatmentrelatedeffect

asnodifferenceswereseeninF1testicularweightsandnopathologicalevidenceofaspermiaortesticularatrophywasseenineitherthelowormiddosegroups.TheNOAELforreproductiveeffectsinmalesandfemaleswas4500ppm(227-750mg/kgbw/d)andtheLOAELwas8000ppm(419-1360mg/kgbw/d)intheF1generationbasedondecreasedreproductiveorganweight.

Developmentaleffectsseeninthetwo-generationstudyoccurredmainlywiththe4500and8000ppmgroupsinF1andF2generations,includingreducedanogenitaldistance,delaysinbalanopreputialseparation,testicularabnormalities,changesinexternalgenitalia,andretentionofthoracicnipples.ThematernalanddevelopmentalNOAELwas1000ppm(50-168mg/kgbw/d),andtheLOAELwas4500ppm(222-750 mg/kg bw/d) based ondecreased anogenital distance inthe F2 male offspring.Inadevelopmentalstudy,overtdevelopmentaleffectswereseenat750mg/kgbw/d,whichincludedanincreaseinresorptions(perlitterandperimplantationsite)andarelateddecrease in live foetusesand an increased incidenceof foetuses with external,visceralandskeletalmalformationscomparedtocontrols.Overtmaternaltoxicitywasnotevidentinthisstudy,althoughtherewasanincreaseinliverweightsatandabove300mg/kgbw/d.ThedevelopmentalNOAELwasestablishedat300mg/kgbw/d,withaLOAELof750mg/kgbw/dbasedonincreasedresorptionsandmalformations.

Overall,thereproductiveanddevelopmentaleffectsofDiHepParesimilartoothertransitionalphthalates(NICNAS,2008).Transitionalphthalateswhichhavebeentestedalldemonstratedeffectsonmalereproductiveorgans,andinducedarecognisablepatternofmalformationsinoffspringincludingdecreasedanogenitaldistance,delayedpreputialseparationandretainedthoracicnipplesinmalepups.Athighdoses,hypospadiasandcryptorchidismareinduced,aswellasincreasedfrequencyofsupernumeraryribs.

6.HumanHealthHazardSummaryTable

Phthalate / AcuteToxicity / IrritationSensitisation / RepeatedDoseToxicity / GeneticToxicity / Carcinogenicity / Fertility / DevelopmentalToxicity
Diisoheptylphthalate
(DiHepP) / OralRat:
LD50>10000
mg/kgbw
DermalRabbit:LD50>3160
mg/kgbw / Skinirritation:Minimaleffects
Eyeirritation:Minimaleffects
Skinsensitisation:Negative / Oral
Rat(2-gen.reprostudy):
NOAEL=50-168
mg/kgbw/d(m-f)LOAEL=222-750
mg/kgbw/d(m-f),
↑liver,kidneyandpituitaryweightswithassociatedhistopathology.
PPnoted. / Invitro:
Negativeinbacterialmutationandchromosomalaberrations
assays
Invivo:Nodata / Rat,Mouse:
Noeffectongapjunctionalintercellular
communication,↑hepaticDNAsynthesisandperoxisomalbeta-oxidation / Rat:
NOAEL=227-
750mg/kgbw/d(m-f)
LOAEL=419-
1360mg/kgbw/d(m-f),
↓reproductiveorganweight / Twogeneration
studyRat:
NOAEL=50-168
mg/kgbw/d(m-f)LOAEL=222-750
mg/kgbw/d(m-f),
↓anogenitaldistanceinF2
Developmentalstudy
Rat:
NOAEL=300
mg/kgbw/dLOAEL=750
mg/kgbw/d,
↑resorptionsandmalformations

PP:peroxisomeproliferation;m-f:male-female;↑:increase;↓:decrease.

Pageintentionallyblankfordouble-sidedprinting.

References

ExxonBiomedicalSciences(1991)Dermalsensitisationtestintheguineapig.Studyno.181221.ExxonBiomedicalSciencesInc.(Unpublishedreport).

ExxonBiomedicalSciences(1995)Microbialmutagenesisinsalmonellamammalianmicrosomeplateincorporationassay.Studyno.195725.ExxonBiomedicalSciencesInc.(Unpublishedreport).

ExxonBiomedicalSciences(1997)Developmentaltoxicitystudyinratswithdiisoheptylphthalate.Studyno.167634.ExxonBiomedicalSciencesInc.(Unpublishedreport).

HazletonLaboratoriesAmerica,Inc.(1991)Mutagenicitytestinaninvitrocytogeneticassay.StudyNo.181232.Unpublishedreport.

HuntingdonResearchCenter(1994)Skinsensitizationintheguineapig(Buehlermethod).

Studyno.Exx12e/940627/SS.HuntingdonResearchCenter(Unpublishedreport).

IARC(2000)IARCMonographsontheEvaluationofCarcinogenicRiskstoHumans:SomeIndustrialChemicalsVol77.Lyon,France,InternationalAgencyforResearchonCancer.

MBResearchLaboratories(1979)Testfororalanddermaltoxicityinrats,andeyeirritationinrabbits.Studyno.MB79-3967.MBResearchLaboratoriesInc.(Unpublishedreport).

McKeeRH,PavkovKL,TrimmerGW,KellerLH,StumpDG(2006)Anassessmentofthepotentialdevelopmentalandreproductivetoxicityofdiisoheptylphthalateinrodents.ReprodToxicol,21:241-252.

MedeirosAM,DevlinDJ,KellerLH(1999)Evaluationofskinsensitisationresponseofdialkyl(C6-C13)phthalateesters.ContactDermatitis,41:287-289.

NICNAS(2008)Phthalatehazardcompendium:asummaryofphysicochemicalandhumanhealthhazarddatafor24ortho-phthalatechemicals.Sydney,NationalIndustrialChemicalsNotificationandAssessmentScheme.

NishiharaT,NishikawaJ,KanayamaT,DakeyamaF,SaitoK,ImagawaM,TakatoriS,KitagawaY,HoriS,UtsumiH(2000)Estrogenicactivitiesof517chemicalsbyyeasttwo-hybridassay.JournalofHealthScience,46(4):282-298.

OECD(2005)SIDSInitialAssessmentReportforDiisoheptylPhthalateforSIAM 20(Draft).OrganizationforEconomicCooperationandDevelopment,Paris,France,19-22April2005.

SmithJH,IsenbergJS,PughGJr,KamendulisLM,AckleyD,LingtonAW,KlaunigJE(2000)ComparativeinvivohepaticeffectsofDiisononylphthalate(DINP)andrelatedC7-C11dialkylphthalatesongapjunctionalintercellularcommunication(GJIC),peroxisomalbeta-oxidation(PBOX),andDNAsynthesisinratandmouseliver.ToxicolSci,54:312-321.

TakeuchiS,IidaM,KobayashiS,JinK,MatsudaT,KojimaH(2005)Differentialeffectsofphthalateestersontranscriptionalactivitiesviahumanoestrogenreceptorsα andβ,andandrogenreceptor.Toxicology,210:223-233.

TodaC,OkamotoY,UedaK,HashizumeK,ItohK,KojimaN(2004)Unequivocaloestrogenreceptor-bindingaffinityofphthalateestersfeauredwithringhydroxylationandproperalkylchainsize.ArchBiochemBiophys,431:16-21

WilResearchLaboratoriesInc.(2003)Adietarytwo-generationreproductivetoxicitystudyofdiisoheptylphthalateinrats.StudyNo.Wil-438002.Unpublishedreport.

ZacharewskiTR,MeekMD,ClemonsJH,WuZF,FieldenMR,MatthewsJB(1998)Examinationoftheinvitroandinvivooestrogenicactivitiesofeightcommercialphthalateesters.ToxicolSci,46:282-293.

Appendix-RobustStudySummaries

Repeated Dose Toxicity (mechanistic study)

dialkylphthalatesat500,1000,6000,10000and12000mg/kgbw/dfor2and4weeks.Osmoticmini-pumps,containing5-bromo-2’-deoxyuridine,weresurgicallyimplantedsubcutaneouslyinanimalsaweekpriortosacrificeinordertoassessthehepaticeffectsofthetreatments.Animalsweresacrificed,weighedandnecropsied.Theliverswereextractedandprocessedtodeterminegapjunctionalintercellular

communication(GJIC),replicativeDNAsynthesisandperoxisomalbeta-oxidationactivity(PBOX).

ResultRelativeliverweightsweresignificantlyelevatedinratsathighdoses(6000mg/kgbw/d)ofallphthalatesafter2and4weeks,exceptDINP-1at2weeksandDnOPat4weeks.Nosignificantincreaseswereseenatthelowdose(1000mg/kgbw/d)exceptDiHepPat2weeks(p<0.05).Inmice,relativeliverweightsweresignificantlyincreasedathighdoses(6000mg/kgbw/d)ofDINP-1,DINP-AandD711Pat2and4weeksandDIDPat2weeks.Lowdoses(500mg/kgbw/d)ofbothisomersofDINPinducedsignificantincreasesinrelativeliverweightafter2weeksonly(p<0.05).

PBOXactivitywassignificantlyincreasedathighdosesinrats(12000mg/kgbw/d)ofallphthalates(10000mg/kgbw/dforDnOP)after2weeks.OnlyhighdosesofDINP-1andDINP-A,DIDPandDIHepPcausedsignificantincreasesinPBOXactivityafter4weeks(p<0.05).Inmice,PBOXactivitywassignificantlyelevatedathighdoses(6000mg/kgbw/d)ofallphthalatesafter2and4weeks.Lowdoses(500mg/kgbw/d)ofDNOPalsocausedasignificantincreaseinPBOXactivity(p<0.05).

GJICwassignificantlyinhibitedinrats(indicatedbyadecreasedtransferofluciferyellowdyethroughadjacenthepatocytes)athighdoses(12000mg/kgbw/d)ofbothisomersofDINPafter2weeks.HighdosesofDINP-AandD711PcausedsignificantGJICinhibitionafter4weeks(p<0.05).Inmice,highdoses(6000mg/kgbw/d)ofDINP-AandDINP-1causedsignificantinhibitionafter2and4weeks,respectively(p<0.05).

PeriportalhepatocellularreplicativeDNAsynthesiswassignificantlyelevatedinratsathighdoses(12000mg/kgbw/d)ofphthalatesafter2and4weeks(exceptDINP-1andD711Pafter4weeks),andlowdoses(1000mg/kgbw/d)ofDiHepPandDIDPafter2and4weeks(p<0.05).Inmice,DNAsynthesiswassignificantlyincreasedathighdoses(6000mg/kgbw/d)ofallDINP-1,DIDPandDiHepPandlowdoses(500mg/kgbw/d)ofDIDP,DiHepPandD711Pafter2weeks.BothdosesofDIDPandhighdosesofDiHepPmaintainedasignificantincreaseinDNAsynthesisafter4weeks(p<0.05).

LiverconcentrationsofDNIP-1anditsprimarymetabolites,monoisononylphthalate-1(MINP-1)andphthalicacid(PA),weresignificantlyhigherthancontrols,inbothratsandmice,atalltreateddosesafter2and4weeks.Thelevelsofbothmetabolitesweresignificantlyhigherthancontrolsintheserum(intactphthalatewasnotdetectableintheserum)inbothspecies.

ConclusionDINPandotherC7-C11phthalatescausedchangesinGJIC,

DNAsynthesis,PBOXandliverweightafter2-4weeksof

treatmentintheliverofratsandmice.

ReferenceSmithJH,IsenbergJS,PughGJr,KamendulisLM,AckleyD,LingtonAW,KlaunigJE(2000)Comparativeinvivohepaticeffectsofdiisononylphthalate(DINP)andrelatedC7-C11dialkylphthalatesongapjunctionalintercellularcommunication

(GJIC),peroxisomalbeta-oxidation(PBOX),andDNAsynthesisinratandmouseliver.ToxicolSci,54:312-321.

GPO Box 58, Sydney NSW 2001, Australia

NATIONALINDUSTRIALCHEMICALSNOTIFICATIONANDASSESSMENTSCHEME

Preface

GPOBox58

Overview

TableofContents

AcronymsandAbbreviations

1.Introduction

2.Identity

2.1Identification of the substance

2.2Physicochemical properties

PropertyValue

4.1Toxicokinetics

Data not reportedin previous evaluations

Conclusion

4.2Acute toxicity

Data not reported in previous evaluations

Conclusion

4.3Irritation

4.3.1Skin irritation

Data not reported in previous evaluations

Effectsonfertility

Developmental effects

Pageintentionallyblankfordouble-sidedprinting.