英国药典2011Prolonged-releaseTamsulosinCapsulesGeneralNoticesProlonged-releaseTamsulosinCapsulesfromdifferentmanufacturers,whilst complyingwiththerequirementsofthemonograph,arenotinterchangeableunless otherwisejustifiedandauthorised.DEFINITIONProlonged-releaseTamsulosinCapsulescontainTamsulosinHydrochloride.Theyare formulatedsothatthemedicamentisreleasedoveraperiodofseveralhours.PRODUCTIONAsuitabledissolutiontestiscarriedouttodemonstratetheappropriatereleaseof TamsulosinHydrochloride.Thedissolutionprofilereflectstheinvivoperformance whichinturniscompatiblewiththedosageschedulerecommendedbythe manufacturer.ThecapsulescomplywiththerequirementsstatedunderCapsulesandwiththe followingrequirements.Contentoftamsulosinhydrochloride,C20H28N2O5S,HCl95.0to105.0%ofthestatedamount.IDENTIFICATIONA.IntheAssay,theprincipalpeakinthechromatogramobtainedwithsolution(1)hasthesameretentiontimeasthatinthechromatogramobtainedwithsolution(2).B.Thelightabsorptionofsolution(1)obtainedintheAssay,AppendixIIBintherange210to400nm,exhibitsasinglemaximumat225nm.TESTSRelatedsubstancesCarryoutthemethodforliquidchromatography,AppendixIIID,usingthefollowing solutions.(1)Mixforatleast15minuteswiththeaidofultrasoundandwithintermittentshakingaquantityofthecapsulescontaining0.8mgofTamsulosinHydrochloridewith10mlof1Mmethanolichydrochloricacid andfilterthrougha0.7-µmglassfibrefilter,to1volumeofthefiltrateadd4volumesof1Mmethanolichydrochloricacid andfilterthrougha0.7-µmglassfibrefilter.(2)Dilute1volumeofsolution(1)to500volumeswithmobilephase.(3)0.00032%w/voftamsulosinhydrochlorideimpuritystandardBPCRSinthemobilephase.(4)Dilute1volumeofsolution(2)to4volumeswithmobilephase.CHROMATOGRAPHICCONDITIONS(a)Useastainlesssteelcolumn(15cm×4.6mm)packedwithoctadecylsilylsilicagelforchromatography(5µm)(NucleosilC18100Åissuitable).(b)Useisocraticelutionandthemobilephasedescribedbelow.(c)Useaflowrateof1.5mlperminute.(d)Useacolumntemperatureof40°.(e)Useadetectionwavelengthof225nm.(f)Inject20µlofeachsolution.(g)Allowthechromatographytoproceedfor40minutes.MOBILEPHASE300volumesofacetonitrilemixedwith700volumesofwatercontaining0.44%v/v perchloricacidand0.15%w/vsodiumhydroxidepreviouslyadjustedtopH2.0with1Msodiumhydroxide.SYSTEMSUITABILITYThetestisnotvalidunlessthechromatogramobtainedwithsolution(3)closely resemblesthechromatogramsuppliedwithtamsulosinhydrochlorideimpurity standardBPCRS.LIMITSInthechromatogramobtainedwithsolution(1):theareaofanypeakcorrespondingto(2R)-N-[2-(2-ethoxyphenoxy)ethyl]-1-(4-methoxyphenyl)propan-2-amineisnotgreaterthan2.5timestheareaoftheprincipal peakinthechromatogramobtainedwithsolution(2)(0.5%);theareaofanyothersecondarypeakisnotgreaterthantheareaoftheprincipal peakinthechromatogramobtainedwithsolution(2)(0.2%);thesumoftheareasofallsecondarypeaksisnotgreaterthan7.5timestheareaof theprincipalpeakinthechromatogramobtainedwithsolution(2)(1.5%).Disregardanypeakwithanarealessthantheareaoftheprincipalpeakinthe chromatogramobtainedwithsolution(4)(0.05%).UniformityofcontentCapsulescontaininglessthan2mgand/orlessthan2%w/wofTamsulosin HydrochloridecomplywiththerequirementsstatedunderCapsulesusingthe followingmethodofanalysis.Carryoutthemethodforliquidchromatography,AppendixIIID,usingthefollowing solutions.(1)Mixthecontentsof1capsulewith10mlof1Mmethanolichydrochloricacidforatleast15minuteswiththeaidofultrasoundandwithintermittentshaking,filterthrougha0.7-µmglassfibrefilter,dilute1volumeofthefiltrateto10volumeswith1Mmethanolichydrochloricacidandfilterthrougha0.7-µmglassfibrefilter.(2)Preparea0.040%w/vsolutionoftamsulosinhydrochlorideBPCRSinmethanol withtheaidofultrasound,coolanddilute1volumeto100volumeswith1Mmethanolichydrochloricacid.