» Collodion contains not less than 5.0 percent, by weight, of pyroxylin.
Pyroxylin 40 g
Ether 750 mL
Alcohol 250 mL
to make about 1000 mL
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.
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 841: between 0.765 and 0.775.
Acidity— Add 5 mL of it to 5 mL of water: the liquid separated from the pyroxylin is not acid to litmus.
Alcohol content 611
Internal standard solution— Place 20 mL of acetone in a glass-stoppered, 100-mL graduated cylinder, dilute with 1,2-dichloroethane to 100 mL, and mix.
Standard solutions— Pipet 10-, 20-, and 30-mL portions of dehydrated alcohol into separate 100-mL volumetric flasks, dilute with 1,2-dichloroethane to volume, and mix.
Standard preparations— Pipet 10 mL of each Standard solution into separate glass-stoppered, 50-mL graduated cylinders. To each add 15 mL of 1,2-dichloroethane, 10 mL of hexane, and 10.0 mL of Internal standard solution, and mix.
Test preparation— Pipet 10 mL of Collodion into a glass-stoppered, 50-mL graduated cylinder containing 15 mL of 1,2-dichloroethane, 10 mL of hexane, and 10.0 mL of 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 50 mL per minute.
Procedure— Inject a suitable volume (about 4 µL) of each Standard preparation and of the Test preparation into 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 solution taken by the formula:
F = CS / RS
in which CS is the concentration of C2H5OH in the Standard solution, in percentage (V/V); and RS is 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:
in which Fa is the average of the individual F values; and RU is the area-ratio of alcohol to acetone observed for the Test preparation. The content of C2H5OH is between 22.0% and 26.0%.
Assay— Pour quickly about 10 mL of Collodion into a tared flask, insert the stopper, weigh the assay charge accurately, remove the stopper, warm on a steam bath, and add 10 mL of water dropwise, with constant stirring. Evaporate the mixture on a steam bath, and dry the residue at 105 for 4 hours. The weight of the pyroxylin so obtained corresponds to not less than 5.0%, by weight, of the assay charge.
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Topic/Question Contact Expert Committee
Monograph Rick G. Schnatz
Manager, Compounding Pharmacy Expert Committee
(CRX05) Compounding Pharmacy05
USP32–NF27 Page 2023