Collodion

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION

Collodion contains NLT 5.0%, by weight, of pyroxylin.

To the Pyroxylin in a suitable container add the Alcohol and Ether, and insert the stopper into the container. Shake the mixture occasionally until the Pyroxylin is dissolved.

[CAUTION-Collodion is highly flammable.]

2 IDENTIFICATION

2.1 A.

Analysis: Expose a thin layer to air, leaving a transparent, tenacious film.

Acceptance criteria: The film of pyroxylin so obtained burns rapidly with a yellow flame.

2.2 B.

Analysis: Mix with an equal volume of water.

Acceptance criteria: A viscid, stringy mass of pyroxylin is produced.

3 ASSAY

3.1 PROCEDURE

Sample: 10 mL

Analysis: Quickly pour the Sample into a tared flask, insert the stopper, and 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 h.

Acceptance criteria: NLT 5.0%, by weight

4 OTHER COMPONENTS

4.1 ALCOHOL DETERMINATION (611)

Internal standard solution: Acetone and 1,2-dichloroethane (20:80) in a glass-stoppered graduated cylinder

Standard stock solutions: Transfer 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 solutions: Mix 10 mL of each Standard stock solution with 15 mL of 1,2-dichloroethane, 10 mL of hexane, and 10.0 mL of Internal standard solution in separate glass-stoppered, 50-mL graduated cylinders.

Sample solution: To 10 mL of Collodion in a glass-stoppered, 50-mL graduated cylinder add 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

• (See Chromatography (621), System Suitability.)
• Mode: GC
• Detector: Thermal conductivity
• Column: 1.8-m x 3.5-mm glass; packing S3
• Temperatures
• Column: 150°
• Injection port: 200"
• Detector: 250°
• Carrier gas: Helium
• Flow rate: 50 mL/min
• Injection volume: 4 µL

Analysis

Samples: Standard solutions and Sample solution

Calculate the relative response factor, F, for each Standard solution taken:

F=C_s/R_s

C_s = concentration of alcohol in the Standard solution, as a percentage (v/v)

R_s = peak response ratio of alcohol to acetone from the respective Standard solution

Calculate the percentage of alcohol (C₂H₂OH) in the portion of Collodion taken:

Result = R_u x F_a

R_u = peak response ratio of alcohol to acetone from the Sample solution

F_a = average of the individual F values

Acceptance criteria: 22.0%-26.0%

5 SPECIFIC TESTS

5.1 SPECIFIC GRAVITY (841): 0.765-0.775

5.2 ACIDITY

Sample: 5 mL

Analysis: Add the Sample to 5 mL of water.

Acceptance criteria: The liquid separated from the pyroxylin is not acid to litmus.

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Package 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.