Basic Principles of Freeze Drying Final

《Basic Principles of Freeze Drying Final》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、Page:1of14TechnicalNote:BASICPRINCIPLESOFFREEZEDRYINGDate:May6,2009Rev1Author:JOHNBARLEY,PRODUCTMANAGER,SPINDUSTRIESINC.OVERVIEWFreezedryingistheremovaloficeorotherfrozensolventsfromamaterialthroughtheprocessofsublimationandtheremovalofboundwatermolec

2、ulesthroughtheprocessofdesorption.Lyophilizationandfreezedryingaretermsthatareusedinterchangeablydependingontheindustryandlocationwherethedryingistakingplace.Controlledfreezedryingkeepstheproducttemperaturelowenoughduringtheprocesstoavoidchangesinthed

3、riedproductappearanceandcharacteristics.Itisanexcellentmethodforpreservingawidevarietyofheat-sensitivematerialssuchasproteins,microbes,pharmaceuticals,tissues&plasma.SUBLIMATIONSublimationiswhenasolid(ice)changesdirectlytoavaporwithoutfirstgoingthroug

4、haliquid(water)phase.Thoroughlyunderstandingtheconceptofsublimationisakeybuildingblocktogainingknowledgeoffreezedrying.Asshownbelowonthephasediagramforwater,lowpressuresarerequiredforsublimationtotakeplace,Sublimationisaphasechangeandheatenergymustbea

5、ddedtothefrozenproductforittooccur.Sublimationinthefreezedryingprocesscanbedescribedsimplyas:1.FREEZE-Theproductiscompletelyfrozen,usuallyinavial,flaskortray.2.VACUUM-Theproductisthenplacedunderadeepvacuum,wellbelowthetriplepointofwater.3.DRY–Heatener

6、gyisthenaddedtotheproductcausingtheicetosublime.criticalpointtriplepointPHASEDIAGRAMOFWATERThisarticlehasbeenwrittenexclusivelyforSPIndustriesaspartofit’sLyoLearneducationalprogram.Pleasedonotreproducewithoutpermission.Page:2of14TechnicalNote:BASICPRI

7、NCIPLESOFFREEZEDRYINGDate:May6,2009Rev1LYOPHILIZATIONPROCESSOVERVIEWThestepsrequiredtolyophilizeaproductinabatchprocesscanbesummarizedasfollows:•Pretreatment/Formulation•Loading/Container(Bulk,Flask,Vials)•Freezing(ThermalTreatment)atatmosphericpressu

8、re•PrimaryDrying(Sublimation)undervacuum•SecondaryDrying(Desorption)undervacuum•Backfill&Stoppering(forproductinvials)underpartialvacuum•RemovalofDriedProductfromFreezeDryerInadditiontoprovidinganextendedshelf-life,successfulfreeze-dryingshoul