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TheAssayofVitaminASoftCapsules,Purpose1.Tostudytheprinciplesandproceduresofmulti-wavelengthspectropho-tometricassaymethod.2.ToexerciseonthespectrophotometricassayofVitaminA.,ProceduresandmethodsVitaminASoftCapsulescontainasolutionofvitaminAinrefinedvegetableoil(removethesolidfatat0),theconcentrationofwhichhasbeenadjustedappropriately.Eachcapsulecontainsnotlessthan90.0%andnotmorethan120.0%ofthelabelledamountofVitaminAactivity.,Method1(VitaminAinEsterFormA)preparationnotdirectlysolubleincyclohexanemaybefractionatedbyextractionorothermeansnotinvolvingsaponification.IfthisisnotpossiblethepreparationisdealtwithasdescribedbelowunderOtherVitaminA,Method2(OtherVitaminA)Mixaquantityofthepreparationbeingexaminedcontainingnotlessthan500UnitsofvitaminAandnotmorethan1goffatwith30mlofabsoluteethanoland3mlofa50%w/wsolutionofpotassiumhydroxide.Boilgentlyunderarefluxcondenserinacurrentofoxygen-freenitrogenfor30minutes,coolrapidlyandadd30mlofwater.Transferthehydrolysatetoaseparatingfunnelusingthree50-mlquantitiesofetherandextractthevitaminAbyshakingfor1minute.Aftercompleteseparationdiscardtheaqueouslayerandwashtheextractwithfour50-mlquantitiesofwater,mixingverycautiouslyduringthefirsttwowashestoavoidtheformationofemulsions.Evaporatetheseparatedextracttoabout5mlandremovetheremainingsolventinacurrentofoxygen-freenitrogenwithouttheapplicationofheat.Dissolvetheresidueinsufficientpropan-2-oltoproduceasolutioncontaining9to15Unitspermlandmeasuretheabsorbanceat300,310,325and334nm.Determinethewavelengthofmaximumabsorption.,Discussions1.WhyarethespectrophotometricassaymethodusedfortheassayofVitaminAinallthepharmacopoeias2.FigureoutalltheequationsforthecalculationofthecontentofVitaminA.,
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