Isopropyl Myristate
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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 Myristate consists of esters of isopropyl alcohol and saturated high molecular weight fatty acids, principally myristic acid. It contains NLT 90.0% of isopropyl myristate (C17H34O2).
2 IDENTIFICATION
A. The retention times of the major peaks of the Sample solution correspond to those of the System suitability solution, as obtained in the Assay.
3 ASSAY
3.1 PROCEDURE
System suitability solution: 5.0 mg/mL of USP Isopropyl Myristate RS and 0.5 mg/mL of USP Isopropyl Palmitate RS in n-hexane Sample solution: 5.0 mg/mL of Isopropyl Myristate in n-hexane
3.1.1 Chromatographic system
(See Chromatography 〈621〉, System Suitability.) Mode: GC
Detector: Flame ionization
Column: 0.32-mm × 15-m fused silica coated with a 1.0-µm layer of stationary phase G27
Temperatures
Injection port: 240°
Detector: 280° Column: See Table 1.
Table 1
| Initial Temperature (°) | Temperature Ramp (°/min) | Final Temperature (°) | Hold Time at Final Temperature (min) |
| 150 | — | 150 | 1 |
| 150 | 6 | 230 | 8 |
Carrier gas: Helium Flow rate: 1.5 mL/min Injection volume: 2.0 µL
Injection type: Split injection, split ratio 10:1 Run time: 22 min
3.1.2 System suitability
Sample: System suitability solution
[NOTE—The relative retention times for isopropyl myristate and isopropyl palmitate are 1.0 and 1.3, respectively.] Suitability requirements
Resolution: NLT 6.0 between the isopropyl myristate and isopropyl palmitate peaks
Tailing factor: NMT 2 for the isopropyl myristate peak
Relative standard deviation: NMT 2.0% Analysis
Sample: Sample solution
Calculate the percentage of isopropyl myristate (C17H34O2) in the portion of Isopropyl Myristate taken:
Result = (rU/rT) × 100
rU = peak area of isopropyl myristate
rT = sum of the peak areas of all the peaks, except the solvent peak
Acceptance criteria: NLT 90.0%
4 IMPURITIES
RESIDUE ON IGNITION 〈281〉: NMT 0.1%
5 SPECIFIC TESTS
SPECIFIC GRAVITY 〈841〉: 0.846–0.854
REFRACTIVE INDEX 〈831〉: 1.432–1.436 at 20°
FATS AND FIXED OILS, Acid Value 〈401〉: NMT 1
FATS AND FIXED OILS, Iodine Value 〈401〉: NMT 1
FATS AND FIXED OILS, Saponification Value 〈401〉: 202–212
6 ADDITIONAL REQUIREMENTS
PACKAGING AND STORAGE: Preserve in tight, light-resistant containers.
USP REFERENCE STANDARDS 〈11〉
USP Isopropyl Myristate RS USP Isopropyl Palmitate RS
