Isopropyl Palmitate

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

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

DOWNLOAD PDF HERE

1 DEFINITION

Isopropyl Palmitate consists of esters of isopropyl alcohol and saturated high molecular weight fatty acids. It contains NLT 90.0% of isopropyl palmitate (C₁₉H₃₈O₂).

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

Procedure

System suitability solution: 5.0 mg/mL of USP Isopropyl Palmitate RS and 0.5 mg/mL of USP Isopropyl Myristate RS in n-hexane

Sample solution: 5.0 mg/mL of Isopropyl Palmitate in n-hexane

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

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

System suitability

Sample: System suitability solution

[Note—The relative retention times for isopropyl myristate and isopropyl palmitate are 0.8 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 6.0 between the isopropyl myristate and isopropyl palmitate peaks

Tailing factor: NMT 2 for the isopropyl palmitate peak

Relative standard deviation: NMT 2.0%

Analysis

Sample: Sample solution

Calculate the percentage of isopropyl palmitate (C₁₉H₃₈O₂) in the portion of Isopropyl Palmitate taken:

Result = (r_U/r_T) × 100

r_U = peak area of isopropyl palmitate

r_T = 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〉: 0.850–0.855

Refractive Index 〈831〉: 1.435–1.438

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〉: 183–193

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

USP Reference Standards 〈11〉

USP Isopropyl Myristate RS

USP Isopropyl Palmitate RS