Isopropyl Rubbing Alcohol

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 

Isopropyl Rubbing Alcohol contains NLT 68.0% and NMT 72.0% of isopropyl alcohol by volume, with the remainder consisting of water, with or without suitable stabilizers, perfume oils, and color additives certified by the FDA for use in drugs. 

2 ASSAY 

Procedure 

Sample: 50.0 mL of Isopropyl Rubbing Alcohol 

Analysis: Transfer the Sample to a 250-mL distilling flask, and add 100 mL of water. Arrange the flask for distillation, distill, and collect 95 mL of distillate in a 100-mL volumetric flask. Dilute with water to volume, and determine the specific gravity of the distillate at 25° (see specific Gravity 〈841〉). 

Acceptance criteria: The specific gravity is 0.955–0.950, corresponding to 68.0%–72.0% of isopropyl alcohol. 

3 SPECIFIC TESTS 

Specific Gravity 〈841〉: 0.872–0.883 at 20° 

Limit of Nonvolatile Residue 

Sample: 50 mL of Isopropyl Rubbing Alcohol 

Analysis: Evaporate the Sample in a tared porcelain dish on a steam bath to dryness, and dry at 105° for 1 h. Acceptance criteria: 0.01%; NMT 5 mg 

Acidity 

Sample solution: To 50 mL of Isopropyl Rubbing Alcohol add about 75 mL of carbon dioxide-free water. 

Analysis: Transfer the Sample solution to a suitable flask, and titrate potentiometrically to a pH of 8.5. 

Acceptance criteria: NMT 1.0 mL of 0.020 N sodium hydroxide is required for neutralization. 

4 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve in tight containers, remote from heat. 

Labeling: Label it to indicate that it is flammable.