Xylitol
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Xylitol.
Xylitol.
»Xylitol contains not less than 98.5percent and not more than 101.0percent of C5H12O5,calculated on the anhydrous basis.
Packaging and storage—
Preserve in well-closed containers.
Identification,Infrared Absorptioná197Kñ—
Test specimen:
undried.
Water,Method Iá921ñ:
not more than 0.5%.
Residue on ignition á281ñ:
not more than 0.5%.
Heavy metals á231ñ—
Dissolve 2g in 25mLof water:the limit is 0.001%.
Reducing sugars—
Dissolve 500mg of Xylitol in 2.0mLof water in a 10-mLconical flask.Into a similar flask,pipet 2mLof a dextrose solution containing 0.5mg per mL.Concomitantly,to each add 1mLof alkaline cupric tartrate TS,heat to boiling,and cool:any turbidity in the xylitol flask is not greater than that in the dextrose flask,in which a reddish brown precipitate forms (0.2%,as dextrose).
Limit of other polyols—
Using the chromatograms obtained in the Assay,separately calculate the percentage of each polyol in the portion of Xylitol taken by the formula:
2500C/W(RU/RS),
in which Cis the concentration,in mg per mL,of the individual polyol in the Standard preparation;Wis the weight,in mg,of Xylitol taken to prepare the Assay preparation;and RUand RSare the peak response ratios of the individual derivatized polyol to that of derivatized erythritol in the chromatograms of the solutions obtained from the Assay preparationand the Standard preparation,respectively.The sum of the polyols found,calculated on the anhydrous basis,is not more than 2.0%.
Organic volatile impurities,Method Iá467ñ:
meets the requirements.
Assay—
Internal standard solution—
Transfer about 88mg of erythritol to a 25-mLvolumetric flask,dissolve in and dilute with water to volume,and mix.
Standard preparation—
Transfer accurately weighed quantities of about 25mg each of L-arabinitol,galactitol,mannitol,and sorbitol to a 100-mLvolumetric flask.Dissolve in and dilute with water to volume,and mix.Transfer 5.0mLof this solution to a 25-mLvolumetric flask,add about 250mg of USP Xylitol RS,accurately weighed,dilute with water to volume,and mix.
Assay preparation—
Transfer about 250mg of Xylitol,accurately weighed,to a 25-mLvolumetric flask,dissolve in and dilute with water to volume,and mix.
Chromatographic system
(see Chromatography á621ñ)—The gas chromatograph is equipped with a flame-ionization detector and a 0.25-mm ×30-m capillary column bonded with a 0.25-µm layer of phase G46.The carrier gas is helium flowing at a rate of about 1mLper minute.The chromatograph is programmed to maintain the column temperature at 170
for 5minutes,then to increase the temperature at a rate of 6per minute to 215,holding at that temperature for 8minutes,then to increase the temperature at a rate of 10per minute to 270,which is held for 14minutes.The temperature of the injection port is about 270,and the detector temperature is about 280.Chromatograph the solution obtained from the Standard preparationas directed for Procedure,and record the peak responses:the relative retention times corresponding to the derivatives of erythritol,L-arabinitol,xylitol,mannitol,galactitol,and sorbitol are about 0.47,0.75,0.81,0.98,0.99,and 1.0,respectively;and the relative standard deviation for the peak area ratios of xylitol to erythritol for replicate injections is not more than 1.5%.
for 5minutes,then to increase the temperature at a rate of 6per minute to 215,holding at that temperature for 8minutes,then to increase the temperature at a rate of 10per minute to 270,which is held for 14minutes.The temperature of the injection port is about 270,and the detector temperature is about 280.Chromatograph the solution obtained from the Standard preparationas directed for Procedure,and record the peak responses:the relative retention times corresponding to the derivatives of erythritol,L-arabinitol,xylitol,mannitol,galactitol,and sorbitol are about 0.47,0.75,0.81,0.98,0.99,and 1.0,respectively;and the relative standard deviation for the peak area ratios of xylitol to erythritol for replicate injections is not more than 1.5%.
Procedure—
Transfer 1.0mLeach of the Standard preparationand the Assay preparationto separate round-bottom,10-mLboiling flasks.To each flask,add 1.0mLof Internal standard solution,and evaporate each of the mixtures under reduced pressure to dryness on a water bath at 60,with the aid of a rotary evaporator.Add 1mLof dehydrated alcohol,shake gently,and evaporate to dryness under the same conditions.Dissolve each residue in 1mLof pyridine.Add 1mLof acetic anhydride to each flask,cap each flask,and mix on a vortex mixer for 30seconds.Store the closed flasks in an oven at 70for 30minutes.Separately inject equal volumes (about 1µL)of the solutions obtained from the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the percentage of C5H12O5in the portion of Xylitol taken by the formula:
,with the aid of a rotary evaporator.Add 1mLof dehydrated alcohol,shake gently,and evaporate to dryness under the same conditions.Dissolve each residue in 1mLof pyridine.Add 1mLof acetic anhydride to each flask,cap each flask,and mix on a vortex mixer for 30seconds.Store the closed flasks in an oven at 70for 30minutes.Separately inject equal volumes (about 1µL)of the solutions obtained from the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the percentage of C5H12O5in the portion of Xylitol taken by the formula:
2500(C/W)(RU/RS),
in which Cis the concentration,in mg per mL,of USP Xylitol RSin the Standard preparation;Wis the weight,in mg,of Xylitol taken to prepare the Assay preparation;and RUand RSare the peak area ratios of derivatized xylitol to derivatized erythritol in the chromatograms of the solutions obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information—
Staff Liaison:Ravi Ravichandran,Ph.D.,Senior Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 3109
Phone Number:1-301-816-8330