Isopropyl Myristate
» Isopropyl Myristate consists of esters of isopropyl alcohol and saturated high molecular weight fatty acids, principally myristic acid. It contains not less than 90.0 percent of C17H34O2.
Packaging and storage
Preserve in tight, light-resistant containers.
Identification
The retention time of the major peaks obtained in the Assay is the same as that of the corresponding peaks obtained from the System suitability solution employed in the Assay.
Specific gravity 841:
between 0.846 and 0.854.
Acid value 401:
not more than 1.
Iodine value 401:
not more than 1.
Saponification value 401:
between 202 and 212.
Refractive index 831:
between 1.432 and 1.436 at 20.
Residue on ignition 281:
not more than 0.1%.
Assay
System suitability solution
Dissolve about 45 mg of USP Isopropyl Myristate RS and 5 mg of USP Isopropyl Palmitate RS in 10.0 mL of n-hexane.
Assay preparation
Dissolve 125 mg of Isopropyl Myristate in 25.0 mL of n-hexane, and mix.
Chromatographic system (see Chromatography 621)
The gas chromatograph is equipped with a flame-ionization detector and a 4-mm × 1.8-m column packed with 10% liquid phase G8 on 100- to 120-mesh support S1A. The carrier gas is nitrogen, flowing at a rate of 45 mL per minute. The column temperature is programmed to rise from 90 to 210 at a rate of 2 per minute and then to maintain at 210 for 8 minutes. The detector temperature is maintained at 280, and the injection port temperature is maintained at 240. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times for isopropyl myristate and isopropyl palmitate are about 1 and 1.3, respectively; the resolution, R, is not less than 6.0 between the peaks due to isopropyl myristate and isopropyl palmitate; the tailing factor for the isopropyl palmitate peak is not more than 2; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Inject about 5 µL of the Assay preparation into the chromatograph, record the chromatogram, and measure the responses for the major peaks. Calculate the percentage of C17H34O2 in the portion of Isopropyl Myristate taken by the formula:
100A/B
in which A is the isopropyl myristate peak response; and B is the sum of the responses of all the peaks in the chromatogram, except the solvent peak.
Auxiliary Information
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Chromatographic Column
USP32NF27 Page 1262
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.
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