Hymetellose
Methylhydroxyethylcellulose.
Cellulose 2-hydroxyethyl methyl ether [9032-42-2].
»Hymetellose is a partly O-(methylated)and O-(2-hydroxyethylated)cellulose.
Labeling—
Label it to indicate the viscosity of a solution (1in 50)at 20
.
.
Identification—
A:
Use the solution prepared in the test for Color of solution.Heat the solution in a water bath while stirring:at a temperature above 50,the solution becomes cloudy or a flocculent precipitate is formed.The solution becomes clear again on cooling.
,the solution becomes cloudy or a flocculent precipitate is formed.The solution becomes clear again on cooling.
B:
Transfer 1mLof the solution from Identificationtest Ato a glass plate,and allow the water to evaporate:a thin film is formed.
C:
To 10mLof the solution from Identificationtest A,add 0.3mLof 2Nacetic acid and 2.5mLof tannic acid TS:a yellowish-white,flocculent precipitate is formed that dissolves in ammonia TS.
D:
In a test tube about 160-mm long,thoroughly mix 1g of Hymetellose with 2g of finely powdered manganese sulfate.Introduce,to a depth of 2cm into the upper part of the tube,a strip of filter paper impregnated with a freshly prepared Diethanolamine–sodium nitroprusside solution.Insert the tube 8cm into a silicone-oil bath at 190to 200.The filter paper becomes blue within 10minutes.Perform a blank test.
to 200.The filter paper becomes blue within 10minutes.Perform a blank test.
Diethanolamine–sodium nitroprusside solution—
Prepare a sodium nitroprusside solution (1in 20)and adjust with 1Nhydrochloric acid to a pHof 9.8.Mix 11mLof this solution with 1mLof a diethanolamine solution (1in 5)in water.
E:
Dissolve 0.2g of Hymetellose completely,without heating,in 15mLof 70%sulfuric acid.Pour the solution while stirring into 100mLof ice water,and dilute with ice water to 250mL.Transfer 1mLof this solution to a test tube,and while cooling in ice water,add dropwise 8mLof sulfuric acid,and mix thoroughly.Heat in a water bath for exactly 3minutes,and immediately cool in ice water.While the mixture is cold,carefully add 0.6mLof ninhydrin TS,and mix well.Allow to stand at 25:a pink color is produced immediately and does not become violet within 100minutes.
:a pink color is produced immediately and does not become violet within 100minutes.
Color of solution—
While stirring,add a portion equivalent to 1.0g of the dried Hymetellose to 50g of carbon dioxide-free water heated to 90.Allow to cool,adjust the weight of the solution to 100g with carbon dioxide-free water,and stir until dissolution is complete.This solution is not more intensely colored than a solution prepared immediately before use by mixing 2.4mLof ferric chloride CSand 0.6mLof cobaltous chloride CSwith Diluentto make 10mL,and diluting 5mLof this solution with Diluentto make 100mL.Make the comparison by viewing the substance and the solution downward in matched color-comparison tubes against a white surface (see Color and Achromicity á631ñ).
.Allow to cool,adjust the weight of the solution to 100g with carbon dioxide-free water,and stir until dissolution is complete.This solution is not more intensely colored than a solution prepared immediately before use by mixing 2.4mLof ferric chloride CSand 0.6mLof cobaltous chloride CSwith Diluentto make 10mL,and diluting 5mLof this solution with Diluentto make 100mL.Make the comparison by viewing the substance and the solution downward in matched color-comparison tubes against a white surface (see Color and Achromicity á631ñ).
Diluent—
Dilute 27.5mLof hydrochloric acid to 1000mLwith water.
Clarity of solution—
Hydrazine sulfate solution—
Transfer 1.0g of hydrazine sulfate to a 100-mLvolumetric flask,dissolve in and dilute with water to volume,and mix.Allow to stand for 4to 6hours before use.[Caution—Hydrazine sulfate is highly toxic.Avoid skin contact.
]
Methenamine solution—
Transfer 2.5g of methenamine to a 100-mLglass-stoppered flask,add 25.0mLof water,insert the glass stopper,and mix to dissolve.
Primary opalescent mixture—
[NOTE—This suspension is stable for 2months.Mix before use,and do not use if it adheres to the container.]To the flask containing Methenamine solution,add 25.0mLof Hydrazine sulfate solution,mix,and allow to stand for 24hours.
Opalescence standard—
[NOTE—Use this suspension within 24hours after preparation.]Transfer 15.0mLof the Primary opalescent mixtureto a 1000-mLvolumetric flask,dilute with water to volume,and mix.
Reference suspension—
Transfer 30.0mLof the Opalescence standardto a 100-mLvolumetric flask,dilute with water to volume,and mix.
Test solution—
Use the solution from the test for Color of solution.
Procedure—
Transfer a sufficient portion of the Test solutionto a test tube of colorless,transparent,neutral glass with a flat base and an internal diameter of 15to 25mm to obtain a depth of 40mm.Similarly transfer a portion of the Reference suspensionto a separate matching test tube.Compare the Test solutionand the Reference suspensionin diffused daylight,viewing vertically against a black background (see Visual Comparisonunder Spectrophotometry and Light-Scattering á851ñ).[NOTE—The Test solutionis to be compared to the Reference suspensionfive minutes after preparation of the Reference suspension.]The Test solutionis not more opalescent than the Reference suspension.
Viscosity á911ñ—
While stirring,add a portion equivalent to 6.0g of the dried Hymetellose to 150g of carbon dioxide-free water heated to 90.Stir with a propeller-type stirrer for 10minutes,place the flask in a bath of ice water,continue the stirring,and allow to remain in the bath of ice water for 40minutes to ensure that dissolution is complete.Adjust the mass of the solution to 300g,and centrifuge the solution to expel any entrapped air.Adjust the temperature of the solution to 20±0.1,and determine the viscosity using a rotational viscosimeter with a shear rate of 10per second:the apparent viscosity is not less than 75%and not more than 140%of the value stated on the label.
.Stir with a propeller-type stirrer for 10minutes,place the flask in a bath of ice water,continue the stirring,and allow to remain in the bath of ice water for 40minutes to ensure that dissolution is complete.Adjust the mass of the solution to 300g,and centrifuge the solution to expel any entrapped air.Adjust the temperature of the solution to 20±0.1,and determine the viscosity using a rotational viscosimeter with a shear rate of 10per second:the apparent viscosity is not less than 75%and not more than 140%of the value stated on the label.
pHá791ñ—
Use the solution from the test for Color of solution:the pHis between 5.5and 8.0.
Loss on drying á731ñ—
Dry about 1.0g of Hymetellose at 105to constant weight:it loses not more than 10.0%of its weight.
to constant weight:it loses not more than 10.0%of its weight.
Residue on ignition á281ñ:
not more than 1.0%,determined on 1.0g.
Heavy metals,Method IIá231ñ:
0.002%.
Chloride á221ñ—
Dilute 1.0mLof the solution from the Color of solutiontest with water to 20mL,and add 1mLof nitric acid and 1mLof silver nitrate TS.Mix,allow to stand for 5minutes protected from direct sunlight,and compare the turbidity,if any,with that produced from a 10-mLaliquot of a control (prepared by diluting 0.71mLof 0.020Nhydrochloric acid to 100mL)in an equal volume of total solution containing the quantities of reagents used in the test (see Visual Comparisonin the section Procedure,under Spectrophotometry and Light-Scattering á851ñ):any turbidity produced by the test specimen does not exceed that of the control preparation (0.5%).
Auxiliary Information—
Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 3019
Pharmacopeial Forum:Volume No.30(3)Page 975
Phone Number:1-301-816-8251