2024年4月21日发(作者：)
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Glycerin
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C
3
H
8
O
3
92.10
1,2,3-Propanetriol.
Glycerol [56-81-5].
»Glycerin contains not less than 99.0percent and not more than 101.0percent of C
3
H
8
O
3
,calculated on the
anhydrous basis.
Packaging and storage— Preserve in tight containers.
USP Reference standards á11ñ— USP Glycerin RS.
Color— Its color,when viewed downward against a white surface in a 50-mLcolor-comparison tube,is not darker than the color
of a standard made by diluting 0.40mLof ferric chloride CSwith water to 50mLand similarly viewed in a color-comparison tube of
approximately the same diameter and color as that containing the Glycerin.
Identification—
A: Infrared Absorption á197Fñ.
B: Prepare the Test solutionand the Resolution solutionas directed in the test for Limit of diethylene glycol and related
a portion of each solution,stepwise if necessary,with water to obtain the Diluted test solutionand the Diluted
resolution solutionhaving concentrations of about 0.1mg per d as directed for Procedurein the test for Limit of
diethylene glycol and related compounds:the retention time of the glycerin peak in the chromatogram of the Diluted test
solutioncorresponds to that obtained in the chromatogram of the Diluted resolution solution.
Specific gravity á841ñ: not less than 1.249.
Residue on ignition á281ñ— Heat 50g in an open,shallow 100-mLporcelain dish until it ignites,and allow it to burn without
further application of heat in a place free from ,moisten the residue with 0.5mLof sulfuric acid,and ignite to constant
weight:the weight of the residue does not exceed 5mg (0.01%).
Water,Method Iá921ñ: not more than 5.0%.
Chloride á221ñ— A7.0-g portion shows no more chloride than corresponds to 0.10mLof 0.020Nhydrochloric acid (0.001%).
Sulfate á221ñ— A10-g portion shows no more sulfate than corresponds to 0.20mLof 0.020Nsulfuric acid (about 0.002%).
Heavy metals á231ñ— Mix 4.0g with 2mLof 0.1Nhydrochloric acid,and dilute with water to 25mL:the limit is 5µg per g.
Limit of chlorinated compounds— Accurately weigh 5g of Glycerin into a dry,round-bottom,100-mLflask,add 15mLof
morpholine,and connect the flask by a ground joint to a reflux gently for the condenser with
10mLof water,receiving the washing in the flask,and cautiously acidify with nitric er the solution to a suitable
comparison tube,add 0.50mLof silver nitrate TS,dilute with water to 50.0mL,and mix:the turbidity is not greater than that of a
blank to which 0.20mLof 0.020Nhydrochloric acid has been added,the refluxing being omitted (0.003%of Cl).
Organic volatile impurities,Method IVá467ñ: meets the requirements.
Organic volatile impurities,Method IVá467ñ: meets the requirements.
Fatty acids and esters— Mix 50g of Glycerin with 50mLof freshly boiled water and 5mLof 0.5Nsodium hydroxide VS,boil the
mixture for 5minutes,cool,add phenolphthalein TS,and titrate the excess alkali with 0.5Nhydrochloric acid m a blank
determination (see Residual Titrationsunder Titrimetry á541ñ):not more than 1mLof 0.5Nsodium hydroxide is consumed.
Limit of diethylene glycol and related compounds—
Resolution solution— Dissolve accurately weighed quantities of diethylene glycol and USP Glycerin RSin water,and dilute
quantitatively,and stepwise if necessary,with water to obtain a solution having a known concentration of about 0.5mg of each
per mL.
Standard solution— Dissolve an accurately weighed quantity of diethylene glycol in water,and dilute quantitatively,and stepwise
if necessary,with water to obtain a solution having a known concentration of about 0.05mg per mL.
Test solution— Transfer 5g of Glycerin,accurately weighed,to a 100-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,a
0.53-mm ×30-m fused-silica analytical column coated with 3.0-µm G43stationary phase,and an inlet liner having an inverted
cup or spiral chromatograph is programmed as lly,the column temperature is equilibrated at 100until
the time of injection,is increased at a rate of 7.5per minute to 220,and is maintained at 220for injection port
temperature is maintained at 220,and the detector temperature is maintained at carrier gas is split flow
ratio is about 10:1,and the linear flow is maintained at about 38cm per tograph the Resolution solution,and
record the peak responses as directed for Procedure:the resolution,R,between diethylene glycol and glycerin is not less than
tograph the Standard solution,and record the peak responses as directed for Procedure:the relative standard
deviation for replicate injections is not more than 15%.
Procedure— Separately inject equal volumes (about 0.5µL)of the Standard solutionand the Test solutioninto the
chromatograph,record the chromatograms,and measure the responses for all the ate the percentage of diethylene
glycol in the portion of Glycerin taken by the formula:
100(C
S
/C
U
)(r
U
/r
S
),
in which C
S
is the concentration,in mg per mL,of diethylene glycol in the Standard solution;C
U
is the concentration,in mg per
mL,of Glycerin in the Test solution;and r
U
and r
S
are the peak responses for diethylene glycol obtained from the Test
solutionand the Standard solution,respectively:not more than 0.1%is ate the percentage of each other
impurity,excluding any solvent peaks,in the portion of Glycerin taken by the formula:
100(r
i
/r
s
),
in which r
i
is the peak response of each individual impurity obtained from the Test solution;and r
s
is the sum of the responses of
all the peaks obtained from the Test solution:not more than 0.1%of any individual impurity,excluding diethylene glycol,is
found;and not more than 1.0%of total impurities,including diethylene glycol,is found.
Assay—
Sodium periodate solution— Dissolve 60g of sodium metaperiodate in sufficient water containing 120mLof 0.1Nsulfuric acid to
make not heat to dissolve the the solution is not clear,pass through a sintered-glass the
solution in a glass-stoppered,light-resistant the suitability of this solution as 10mLinto a 250-
mLvolumetric flask,dilute with water to volume,and about 550mg of Glycerin dissolved in 50mLof water add 50mLof the
diluted periodate solution with a a blank,pipet 50mLof the solution into a flask containing 50mLof the
solutions to stand for 30minutes,then to each add 5mLof hydrochloric acid and 10mLof potassium iodide TS,and rotate to
to stand for 5minutes,add 100mLof water,and titrate with 0.1Nsodium thiosulfate,shaking continuously and adding
3mLof starch TSas the endpoint is ratio of the volume of 0.1Nsodium thiosulfate required for the glycerin–
periodate mixture to that required for the blank should be between 0.750and 0.765.
Procedure— Transfer about 400mg of Glycerin,accurately weighed,to a 600-mLbeaker,dilute with 50mLof water,add
bromothymol blue TS,and acidify with 0.2Nsulfuric acid to a definite green or greenish yellow lize with 0.05Nsodium
hydroxide to a definite blue endpoint,free from green e a blank containing 50mLof water,and neutralize in the same
hydroxide to a definite blue endpoint,free from green e a blank containing 50mLof water,and neutralize in the same
50mLof the Sodium periodate solutioninto each beaker,mix by swirling gently,cover with a watch glass,and allow
to stand for 30minutes at room temperature (not exceeding 35)in the dark or in subdued 10mLof a mixture of equal
volumes of ethylene glycol and water,and allow to stand for each solution with water to about 300mL,and
titrate with 0.1Nsodium hydroxide VSto a pHof 8.1±0.1for the specimen under assay and 6.5±0.1for the blank,using a
mLof 0.1Nsodium hydroxide,after correction for the blank,is equivalent to 9.210mg of C
3
H
8
O
3
.
Auxiliary Information— Staff Liaison:Justin Lane,B.S.,Scientific Associate
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 911
Pharmacopeial Forum:Volume No.28(4)Page 1245
Phone Number:1-301-816-8323
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