Collodion
»Collodion contains not less than 5.0percent,by weight,of pyroxylin.
Pyroxylin 40g
Ether 750mL
Alcohol 250mL
To make about 1000mL
Add the Alcohol and the Ether to the Pyroxylin contained in a suitable container,and insert the stopper into the container well.Shake the mixture occasionally until the Pyroxylin is dissolved.
Caution—Collodion is highly flammable.
Packaging and storage— Preserve in tight containers,at a temperature not exceeding 30,remote from fire.
Labeling— The label bears a caution statement to the effect that Collodion is highly flammable.
Identification—
A: When exposed to air in a thin layer,it leaves a transparent,tenacious film.The film of pyroxylin so obtained burns rapidly,with a yellow flame.
B: When mixed with an equal volume of water,it yields a viscid,stringy mass of pyroxylin.
Specific gravity á841ñ: between 0.765and 0.775.
Acidity— Add 5mLof it to 5mLof water:the liquid separated from the pyroxylin is not acid to litmus.
Alcohol content á611ñ—
Internal standard solution— Place 20mLof acetone in a glass-stoppered,100-mLgraduated cylinder,dilute with 1,2-dichloroethane to 100mL,and mix.
Standard solutions— Pipet 10-,20-,and 30-mLportions of dehydrated alcohol into separate 100-mLvolumetric flasks,dilute with 1,2-dichloroethane to volume,and mix.
Standard preparations— Pipet 10mLof each Standard solutioninto separate glass-stoppered,50-mLgraduated cylinders.To each add 15mLof 1,2-dichloroethane,10mLof hexane,and 10.0mLof Internal standard solution,and mix.
Test preparation— Pipet 10mLof Collodion into a glass-stoppered,50-mLgraduated cylinder containing 15mLof 1,2-dichloroethane,10mLof hexane,and 10.0mLof Internal standard solution,mix,and allow the precipitate to settle.
Chromatographic system— Under typical conditions,the instrument is equipped with a thermal conductivity detector,and it contains a 1.8-m ×3.5-mm glass column containing packing S3;the injection port,the detector,and the column temperatures are maintained at 200,250,and 150,respectively;and helium is used as the carrier gas,at a flow rate of about 50mLper minute.
Procedure— Inject a suitable volume (about 4µL)of each Standard preparationand of the Test preparationinto a suitable gas chromatograph,and record the chromatograms (so as to obtain about 25%of maximum recorder response for the least concentrated solution).Calculate the relative response factor,F,for each Standard solutiontaken by the formula:
F=CS/RS,
in which CSis the concentration of C2H5OHin the Standard solution,in percentage (V/V);and RSis the area-ratio of alcohol to acetone observed for the respective Standard preparation.Calculate the percentage of alcohol,CU,in the test specimen taken by the formula:
CU=FaRU,
in which Fais the average of the individual Fvalues;and RUis the area-ratio of alcohol to acetone observed for the Test preparation.The content of C2H5OHis between 22.0%and 26.0%.
Assay— Pour quickly about 10mLof Collodion into a tared flask,insert the stopper,weigh the assay charge accurately,remove the stopper,warm on a steam bath,and add 10mLof water dropwise,with constant stirring.Evaporate the mixture on a steam bath,and dry the residue at 105for 4hours.The weight of the pyroxylin so obtained corresponds to not less than 5.0%,by weight,of the assay charge.
Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 542
Phone Number:1-301-816-8389