(eye'' soe proe' pil pal' mi tate).
» Isopropyl Palmitate consists of esters of isopropyl alcohol and saturated high molecular weight fatty acids. It contains not less than 90.0 percent of C19H38O2.
Packaging and storage Preserve in tight, light-resistant containers.
USP Reference standards 11
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 0.850 and 0.855.
Acid value 401: not more than 1.
Iodine value 401: not more than 1.
Saponification value 401: between 183 and 193.
Refractive index 831: between 1.435 and 1.438.
Residue on ignition 281: not more than 0.1%.
System suitability solution Dissolve about 45 mg of USP Isopropyl Palmitate RS and 5 mg of USP Isopropyl Myristate RS in 10.0 mL of n-hexane.
Assay preparation Dissolve 125 mg of Isopropyl Palmitate 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 C19H38O2 in the portion of Isopropyl Palmitate taken by the formula:
100A/Bin which A is the isopropyl palmitate peak response; and B is the sum of the responses of all the peaks in the chromatogram, except the solvent peak.
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USP35NF30 Page 1831