常用软膏剂的制备

常用软膏剂的制备

0542327仝贇

Preparationofointments

Ointmentsaresemi-solidpreparationsmadeofmedicamentsandsuitablebases,whichareintendedforexternalapplicationtotheskin.Ointmentbasesrecognizedforuseasvehiclesdistinguishedintothreegeneralclasses:theoleaginousbases,theemulsionbases,andthewater–solublebases.

Therearethreegeneralmethods:themethodofgrindingandmixing,themethodofmeltingandmixing,themethodofemulsification.

Ophthalmicointmentsareointmentsforapplicationtotheeyewhosebasesgeneralincludeliquidparaffin,Vaselineandwoolfat.Specialprecautionsmustbetakeninthepreparationofophthalmicointments.Theyaremanufacturedfromsterilizedingredientsunderrigidlyasepticconditions.Theointmentbasethatisselectedmustbewithoutanyirritationtoeye.

Equipments:evaporating,waterbath,electricfurnace,analyticalbalance,thermometer,microscopeetc.

Materials:Stearicacid,glycerolmonostearate,Vaseline,glycerol,liquidparaffin,triethanolamine,calciumhydroxide,CMC-Na,span80,nonoxynol-10,distilledwateretc.Procedures:

1.

O/Wemulsionbase

FormulationStearicacid

4.8gGlycerolmonostearate

1.4gLiquidparaffin

2.4gVaseline

0.4g

TokeepwaterWoolfat

2.0gTriethanolamine

0.16gDistilledwateraddupto

40.0g

Preparation:

Addstearicacid,glycerolmonostearate,liquidparaffin,Vaselineandwoolfatintoevaporatingdish,whichthemixtureisusedasoilphase.Addtriethanolamineanddistilledwaterintobeaker,whichthesolutionisusedasawaterphase.Thetwocontainersareheatedto80°Cinwaterbathandkeptuntilmeltingcompletely.Pouroilphaseintowaterphaseslowly,andstirthemfully.Coolatroomtemperature,thentheO/Wemulsionbasecanbegot.2.

W/Oemulsionbase

Formulation:Glycerolmonostearate

0.85gBeeswax

5.25gParaffin

3.75gStearicacid

0.625gLiquidparaffin

20.5gVaseline

3.35g

TokeepwaterSpan80

0.5gcalciumhydroxide

0.05gEthylparaben

0.1gDistilledwater

10.0gEssence

2drops

Preparation:

Addglycerolmonostearate,paraffinandstearicacidintotheevaporatingdishthatisabovewaterbath.Whenthemixtureismelted,addVaseline,liquidparaffinandaluminumdistearateintoit.Theabovemixtureisusedastheoilphase.Calciumhydroxideandethylparabenaredissolvedindistilledwater.Thedegreeofwaterisabout80°C.Thesolutionisusedasthewaterbase.Aclockwisestirringisneededwhenaddwaterphaseintooilphase.Coolthebasetotheroomtemperature,thentheW/Oemulsionbasecanbegot.

ResultsandDiscussion:

ThefirstO/Wisakindofthickwhiteointment,whilethesecondisabityellow,andtheformeristhinthanthelatter.Boththetwoproductshaveakindofsmell.

Inthepreparationofointments,weshouldkeepthetemperatureat80°Cforthereasonofgettingthereactionstarted.Andthetemperatureofthewaterphaseshouldbehigherthanthatoftheoilphase,underthiscondition,wecanmakesurethattheoilphaseandthewatergetintouchandhaveacompletereaction.

Theexperimentisconsideredtobeasuccessfulone.

References:

软膏剂（Ointments）

软膏剂（Ointments）指药物与适宜基质均匀混合制成的具有一定稠度的半固体外用制剂。常用基质分为油脂性、水溶性和乳剂型基质，其中用乳剂基质制成的易于涂布的软膏剂称乳膏剂。

因药物在基质中分散状态不同，用溶液型软膏剂和混悬型软膏剂之分。溶液型软膏剂为药物溶解或共熔于基质或基质组分中制成的软膏剂，混悬型软膏剂为药物细粉均匀分散与基质中制成的软膏剂。

软膏剂基质可分为油脂性基质和水溶性基质。油脂性基质常用的有凡士林、石蜡、液体石蜡、硅油、蜂蜡、硬脂酸、羊毛脂等，水溶性基质主要有聚乙二醇。

乳膏剂：系指药物溶解或分散于乳状液型基质中形成的均匀的半固体外用制剂。乳膏剂由于基质不同，可分为水包油型乳膏剂和油包水型乳膏剂。

乳膏剂常用的乳化剂可分为水包油型和油包水型。水包油型乳化剂有钠皂、三乙醇胺皂类、脂肪醇硫酸（酯）钠类（十二烷基硫酸钠）和聚山梨酯类；油包水型乳化剂有钙皂、羊毛脂、单甘油酯、脂肪醇等。

软膏剂和乳膏剂基质应均匀、细腻，涂于皮肤或黏膜上应无刺激性，混悬型软膏剂中不溶性固体药物应预先用适宜的方法磨成细粉，确保粒度符合规定。

软膏剂和乳膏剂根据需要可加入保湿剂、防腐剂、增稠剂、抗氧剂及透皮促进剂。

软膏剂和乳膏剂应具有适当的粘稠度，应易涂布于皮肤或粘膜上，不融化，粘稠度随季节变化应很小。

软膏剂和乳膏剂应无酸败、异臭、变色、变硬，乳膏剂不得有油水分离及胀气现象。

除另有规定外，软膏剂应遮光密闭保存，乳膏剂应遮光保存，宜置25℃

Ointments

Ointmentsareusedtopicallyforseveralpurposes,e.g.,asprotectants,antiseptics,emollients,antipruritics,kerotolytics,andastringents.Thevehicleorbaseofanointmentisofprimeimportanceifthefinishedproductisexpectedtofunctionasanyoneoftheabovecategories.Inthecaseofaprotectiveointment,itservestoprotecttheskinagainstmoisture,air,sunraysandotherexternalfactors.Itisnecessarythattheointmentneitherpenetratesthehumanskinbarriersnorfacilitatestheabsorptionofsubstancesthroughthisbarrier.Anantisepticointmentisusedtodestroyorinhibitthegrowthofbacteria.Frequentlybacterialinfectionsaredeeplyseated;abasewhichhasthecapacitytoeitherpenetrateordissolveandreleasethemedicationeffectivelyisthereforedesired.Ointmentsusedfortheiremollienteffectshouldbeeasytoapply,benon-greasyandeffectivelypenetratetheskin.

Therearefive(5)classesortypesofointmentbaseswhicharedifferentiatedonthebasisoftheirphysicalcomposition.Theseare:oleaginousbasesabsorptionbaseswaterinoilemulsionbasesoilinwateremulsionbaseswatersolubleorwatermisciblebases

Eachointmentbasetypehasdifferentphysicalcharacteristicsandtherapeuticusesbaseduponthenatureofitscomponents.Thefollowingtablesummarizesthecomposition,properties,andcommonusesofeachofthefivetypes.FormoreinformationconsultRemington's.

Toincorporateaninsolubledrugintothesebases,pulverizethepowderonthepilltileorwithamortarandpestle(above/right).Usealevigatingagenttowetthepowderandthenincorporatethewettedpowderintotheointmentbase.Generally,theamountofdrugtobeincorporatedintotheointmentwillbemuchlessthantheamountofointment.Inotherwords,asmallamountofdrugwillbeincorporatedintoalargeamountofointment.Theprocessofgeometricdilutionwill"diluted"thedrugintotheointment.Geometricdilutioninvolvesaseriesofdilutionsteps.Itbeginsbyincorporatingthedrugintoanamountofointmentofapproximatelythesamesize.Thenasecondamountofointmentapproximatelyequaltothefirstmixtureisaddedandmixed.Thisstepwisedilutionprocessiscontinuedalloftheointmenthasbeenused.

Agoodlevigatingagentismineraloilsinceitiscompatiblewitholeaginousbases.Sometimesusingasmallquantityofthebaseitselfasthelevigatingagentissufficient.

Solubledrugscanbeincorporatedintooleaginousbasesbyfusion.Thebaseisliquefiedoverlowheat(nottoexceed70°C)andthenthedrugisaddedtothemoltenbase.Themixtureisthenallowedtocoolwithoccasionalstirring.

Showhowtoincorporatedadrugintoanointmentusinggeometricdilution&2spatulas

Incorporatinginsolubledrugsintothesebasescanbedonemechanicallyorbyfusion.Thefinaldestination(internalorexternalphaseoftheemulsion)ofthedrugmustbeconsideredwhenselectingalevigatingagent.Ifthedrugwillresideintheinternalphase(waterphase),thenthelevigatingagentshouldbewatersolubleormiscible.Water,glycerin,alcohol,orpropyleneglycolwouldbesuitablelevigatingagents.Ifthedrugwillresideintheexternalphase,thenmineraloilshouldbeused.

Watersolubleingredientscanbeaddedtothewaterphaseofthew/oemulsion.Ifthedrugwilldissolveinasmallamountofwater,theaqueoussolutioncanbeaddeddirectlytothebaseusingapilltileandspatula.Ifalargerquantityofwaterisneededtosolubilizethedrugorifanaqueoussolutionisbeingaddedtothebase,heatmaybeneededtocompoundtheformulation.Itmaybenecessarytoaddadditionalemulsifiertotheemulsiontoaccommodatetheaddedwater.Somecommercialemulsionsdohavethenecessaryexcessemulsifier.

W/OEmulsionBases

Oilsandinsolublepowderscanbedirectlyincorporatedintotheexternalphaseusingapilltileandspatula.Ifalevigatingagentistobeusedwiththeinsolublepowders,itshouldbemisciblewiththeoilphase;mineraloilwouldbeasuitableagent.Levigatingagentsmaybeneededwithlargerquantitiesofinsolublepowders.Iftheinsolublepowderhasadifferentsaltformthatisoilsoluble,considerationshouldbegiventousingthatsaltform.

Thesamecommentsthatapplytoincorporatingwatersolubleingredientsintoabsorptionbasesalsoapplytow/oemulsionbases.

O/WEmulsionBases

Watersolublepowderscanbedirectlyincorporatedintotheexternalphaseusingapilltileandspatula.Ifthepowderisinsoluble,thelevigatingagentshouldbewatermisciblesoglycerin,propyleneglycol,polyethyleneglycol(PEG)300or400,oralcoholwouldbeacceptable.Iftheinsolublesubstancehasadifferentsaltformthatisaqueoussoluble,considerationshouldbegivento