Myristyl 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

Myristyl Alcohol contains NLT 90.0% and NMT 102.0% of myristyl alcohol (C₁₄ H₃₀ O), the remainder consisting chiefly of related alcohols. It is obtained from sources of vegetable, animal, or synthetic origin.

2 IDENTIFICATION

A. Chromatographic Identity

Analysis: Proceed as directed in the Assay.

Acceptance criteria: The retention time of the major peak of the Sample solution, excluding the solvent and internal standard peaks, corresponds to the myristyl alcohol peak of the Standard solution.

3 ASSAY

Procedure

Internal standard solution: 1 mg/mL of 1-pentadecanol (internal standard) in ethanol

System suitability solution: Prepare 1 mg/mL of USP Cetyl Alcohol RS, 1 mg/mL of USP Stearyl Alcohol RS, and 1 mg/mL of USP Oleyl Alcohol RS in Internal standard solution, and heat the solution in a sealed container in a 50° water bath until all fatty alcohols are dissolved. Allow the solution to cool to room temperature, and mix well.

Standard solution: 1.0 mg/mL of USP Myristyl Alcohol RS in Internal standard solution

Sample solution: 1.0 mg/mL of Myristyl Alcohol in Internal standard solution

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: GC

Detector: Flame ionization

Column: 0.25-mm × 30-m fused-silica capillary column, coated with a 0.25-µm layer of phase G7

Temperatures

Carrier gas: Hydrogen

Flow rate: 2.0 mL/min, constant flow mode

Injection volume: 1 µL

Injection type: Split injection; split ratio is 100:1

Liner: Single taper, low pressure drop liner with deactivated wool

Run time: 15 min

System suitability

Samples: System suitability solution and Standard solution

[Note—See Table 2 for the relative retention times.]

Table 2

Suitability requirements

Resolution: NLT 30 between the cetyl alcohol and stearyl alcohol peaks; NLT 2.0 between the stearyl alcohol and oleyl alcohol peaks, System suitability solution

Tailing factor: 0.8–1.8 for the myristyl alcohol and 1-pentadecanol peaks, Standard solution

Relative standard deviation: NMT 1%, using the area ratio of myristyl alcohol to 1-pentadecanol, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of myristyl alcohol (C₁₄ H₃₀ O) in the portion of Myristyl Alcohol taken:

Result = (R_u /R_s ) × (C_s /C_u ) × 100

R_u = peak response ratio of myristyl alcohol to the internal standard (peak response of myristyl alcohol/peak response of the internal standard) from the Sample solution

R_s = peak response ratio of myristyl alcohol to the internal standard (peak response of myristyl alcohol/peak response of the internal standard) from the Standard solution

C_s = concentration of USP Myristyl Alcohol RS in the Standard solution (mg/mL)

C_u = concentration of Myristyl Alcohol in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–102.0%

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.1%, determined on 2 g

Limit of Related Fatty Alcohols

Solution A: 1 mg/mL of 1-pentadecanol in ethanol

Resolution solution: Prepare 1 mg/mL of USP Lauryl Alcohol RS, 1 mg/mL of USP Myristyl Alcohol RS, 1 mg/mL of USP Cetyl Alcohol RS, 1 mg/mL of USP Stearyl Alcohol RS, and 1 mg/mL of USP Oleyl Alcohol RS in Solution A. Heat the solution in a sealed container in a 50° water bath until all fatty alcohols are dissolved. Allow the solution to cool to room temperature, and mix well. Dilute the solution with Ethanol to obtain a solution containing 0.05 mg/mL each of USP Lauryl Alcohol RS, USP Myristyl Alcohol RS, USP Cetyl Alcohol RS, 1-pentadecanol, USP Stearyl Alcohol RS, and USP Oleyl Alcohol RS.

Sample solution: 1 mg/mL of Myristyl Alcohol in ethanol

Chromatographic system: Proceed as directed in the Assay, except for the split ratio.

Injection type: Split injection; split ratio is 5:1

System suitability

Sample: Resolution solution

[Note—See Table 3 for the relative retention times.]

Table 3

Suitability requirements

Resolution: NLT 15 between myristyl alcohol and 1-pentadecanol peaks; NLT 30 between the cetyl alcohol and stearyl alcohol peaks; NLT 2.0 between the stearyl alcohol and oleyl alcohol peaks

Analysis

Samples: Resolution solution and Sample solution

Identify each related fatty alcohol peak in the Sample solution based on that in the Resolution solution.

Calculate the percentage of each related fatty alcohol or any unspecified impurity in the portion of Myristyl Alcohol taken:

Result = (r_u /r_t ) × 100

r_u = peak response of each related fatty alcohol (or any unspecified impurity) from the Sample solution

r_t = sum of all the peak responses excluding peak responses due to solvent from the Sample solution

Acceptance criteria: Disregard peaks that are less than 0.05% for any unspecified impurities, and any peaks due to solvent.

Sum of unspecified impurities: NMT 1%

Sum of related fatty alcohols and unspecified impurities: NMT 10.0%

5 SPECIFIC TESTS

Fats and Fixed Oils, Acid Value 〈401〉: NMT 2

Fats and Fixed Oils, Iodine Value 〈401〉: NMT 1

Fats and Fixed Oils, Hydroxyl Value 〈401〉: 250–267

Water Determination, Method I 〈921〉: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

Labeling: Label it to indicate whether it is derived from vegetable, animal, or synthetic sources.

USP Reference Standards 〈11〉

USP Cetyl Alcohol RS

USP Lauryl Alcohol RS

USP Myristyl Alcohol RS

USP Oleyl Alcohol RS

USP Stearyl Alcohol RS