Flexible 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

Prepare Flexible Collodion as follows.

Weigh the ingredients, successively, into a dry, tared bottle. Insert the stopper in the bottle, and shake the mixture until the Camphor is dissolved.

2 IDENTIFICATION

A.

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

Acceptance criteria: The lm exhibits a distinct odor of camphor. The lm of pyroxylin so obtained burns rapidly with a yellow ame. \

B.

Analysis: Mix with an equal volume of water.

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

3 OTHER COMPONENTS

Alcohol Determination 〈611〉

Internal standard solution: Acetone and 1,2-dichloro ethane (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 asks, 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 Flexible 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.

3.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: GC

Detector: Thermal conductivity

Column: 1.8-m × 3.5-mm glass; support S3

Temperatures

Column: 150°

Injection port: 200°

Detector: 250°

Carrier gas: Helium

Flow rate: 50 mL/min

Injection volume: 4 µL

3.2 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 (C₂H₅OH) in the portion of Flexible Collodion taken:

Result = R_U × 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: 21.0%–25.0%

4 SPECIFIC TESTS

Specific Gravity 〈841〉: 0.770–0.790

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in tight containers, at a temperature not exceeding 30°, remote from re.

Labeling: The label bears a caution statement to the effect that Flexible Collodion is highly ammable.