《药剂学》课程双语教学方法建设的工作进展

1Chapter3Powdersandgranules2007.1.142DefinitionofpowdersConnotation(涵义)1,thephysicalformofamaterialadrysubstancecomposedoffinelydividedparticlesTheuseofpowderedsubstancesinthepreparationofotherdosageformsisextensive.Forexample,a.tabletsandcapsules;b.liquiddosageforms(solutionsorsuspensions);c.ointmentsandcreams.Connotation2,atypeofpharmaceuticalpreparationamedicatedpowderintendedforinternal(i.e.,oralpowder)orexternal(i.e.,topicalpowder)useTheuseofmedicatedpowdersperseintherapeuticsislimited3DefinitionofgranulesGranulesarepreparedagglomeratesofpowderedmaterials,andmaybeusedperseforthemedicinalvalueoftheircontentortheymaybeusedforpharmaceuticalpurposes,asintableting.4Thechemicalandphysicalfeaturesofsolidmaterialsusedinthepreparationofpharmaceuticalproducts1.morphology(形态学)2.purity(纯度)3.solubility(溶解度)4.stability(稳定性)5.particlesize(粒径)6.uniformity(均一性)7.compatibility(相容性)withanyotherformulationcomponentschemicalandpharmaceuticalprocessingefficientproductionofafinisheddosageformandoptimumtherapeuticefficacyTherequirementsforthematerialofsoliddosageformMixingthoroughlyFlowabilityFillingproperty5ParticlesizeandanalysisTheparticlesizegradationinUSP•Verycoarse（最粗粉）•Coarse（粗粉）•Moderatelycoarse（中粉）•Fine（细粉）•Veryfine（最细粉）Thisgradationsystemisbasedonsievingmethod（筛分法）,andisrelatedtotheproportionofpowderthatiscapableofpassingthroughtheopeningofstandardizedsievesofvaryingdimensionsinaspecifiedtimeperiodundershaking.6Particlesizeandanalysistypicalparticlesizeofgranules:4-to12-sieveGranulesfallwithintherangeof12-to20-sievearesometimesusedintabletmaking.Thepurposeofparticlesizeanalysisinpharmacyistoobtainquantitativedataonthesize,sizedistribution,andshapesofdrugandnondrugcomponentstobeusedinpharmaceuticalformulations7ParticlesizeandanalysisParticlesizecaninfluenceavarietyofimportantfactors:•Dissolutionrate(particlesize↓→surfacearea↑)•Suspendability(混悬性)(suspensions;0.5-10μm)•Uniformdistributiontoensuredose-to-dosecontentuniformity(powders,granulesandtablets)•Penetrability(inhalers;1-5μm,depositiondeepintherespiratorytract)•Nongrittiness(无砂砾感)(dermalointments,creams,andophthalmic(眼科)preparations;50-100μm)8ParticlesizeandanalysisThemethodsusedforthedeterminationofparticlesize•Sieving40to9500μm•Microscopy0.2to100μmprovideinformationofshape•Sedimentationrate0.8to300μm•Lightenergydiffractionorlightscattering0.2to500μmlaserscattering0.02to2000μmphotoncorrelationspectrum•LaserHolography1.4to100μmprovideinformationofshape•Cascadeimpaction(级联撞击)Acombinationoftheabovemethodsandothersisoftenpreferredtoprovidegreaterassuranceofsizeandshapeparameters.9ParticlesizeandanalysisStokes’law/relationηηv18gddD9gdd2r212212v:velocityofthesedimentationincm/secr:particleradiusincmD:particlediameterincmd1:densityoftheparticleing/mld2:densityoftheliquiding/mlg=gravitationalconstant=980.7cm·sec-2η＝theviscosityofthemediuminpoises,i.e.,g·cm-1·sec-1(poise)incgsunitsIncidentally,thewaterat20℃hasaviscosityofapproximatelyonecentipoises(0.01poise).1g·cm-1·sec-1=1p=100cp=0.1Pa·s1cp=1mPa·s212118gddvD10Onmicromeritics(微粒学,粉粒学)Micromeriticsisthescienceofsmallparticles;aparticleisanyunitofmatterhavingdefinedphysicaldimensions.Micromeriticsincludesanumberofcharacteristicsincludingparticlesize,particlesizedistribution,particleshape,angleofrepose(休止角),porosity(空隙率),truevolume(真实体积),bulkvolume(总体积、松容积),apparentdensity(松密度)andbulkiness(膨松度).Areductioninapowder’sparticlesizeincreasesthenumberofparticlesandthepowder’stotalsurfacearea.11particlesizedeterminedbymicroscopicmethodsizegroupofcountedparticles/μmMiddlevalueμm“d”Numberofparticlespergroup“n”“nd”40-60501575060-807025175080-10090958550100-12011014015400120-1401308010400∑n=355∑nd=368508.10335536850nnddav12particlesizedeterminedbysievingmethodSeivenumberArithmeticmeanopening(mm)Weightretained(G)%Retained%Retained×Meanopening20/400.63015.514.39.00940/600.33525.823.77.93960/800.21448.344.49.50280/1000.16315.614.32.330100/1200.1373.53.30.452108.7100.029.232mm2923.0100232.29100sizeave%retaineddav13Angleofrepose（休止角）Theangleofreposeisaparameterusedtoestimatetheflowabilityofapowder.hrθrhtangentθPowderswithlowanglesofreposewillflowfreelyandpowderswithhighanglesofreposewillflowpoorly.Anumberoffactors,includingshapeandsize,determinetheflowabilityofpowders.Shape:Sphericalparticlesflowbetterthanneedles.Size:Veryfineparticlesdonotflowasfreelyaslargeparticles.a)250-2000μm:flowfreelyiftheshapeisamenableb)75-250μm:mayflowfreelyorcauseproblems,dependingonshapeandotherfactorsc)lessthan100μm:Flowisproblemwithmostsubstances.14Othercharacteristicsofmicromeritics100VoidPorositybulkbulkVVVVoidbulkaVsampletheofweight)density(ρapparent100VVVPorositybulkbulkVsampletheofweight)density(ρtrueta膨松度ρ1B)bulkiness(15Comminution(粉碎)ofdrugsDefinitionComminutionistheprocessofreducingtheparticlesizeofasolidsubstancetoafinerstateofsubdivisions.Itisusedtoa)facilitatecrudedrugextraction,b)increasethedissolutionratesofadrug,c)aidintheformulationofpharmaceuticallyacceptabledosageforms,andd)enhancetheabsorp