Corn oil

[Description] This product is a pale yellow, clear, oily liquid; it possesses a faint, characteristic odor and a bland taste. It is miscible with diethyl ether, chloroform, petroleum ether, and acetone, and is slightly soluble in ethanol. Relative Density: The relative density of this product (Appendix VI A) shall be between 0.915 and 0.923. Refractive Index: The refractive index of this product (Appendix VI F) shall be between 1.472 and 1.475. Acid Value: Shall not exceed 0.6 (Appendix VII H). Saponification Value: Shall be between 187 and 195 (Appendix VII H). Iodine Value: Shall be between 108 and 128 (Appendix VII H).
[Tests] Fatty Acid Composition: Transfer 8–10 drops (weighing approximately 150–250 mg) of this product into a 50 mL volumetric flask (taking care not to let the drops touch the flask walls during addition). Add 4 mL of 0.5 mol/L methanolic potassium hydroxide solution, and heat under reflux in a 65°C water bath. Once the oil droplets have dissolved, allow the solution to cool. Add 5 mL of 15% methanolic boron trifluoride solution, and heat under reflux in a 65°C water bath for 2 minutes. Allow to cool again, then add 1–4 mL of *n*-hexane. Heat in a 65°C water bath for 1 minute, then allow to cool. Add saturated sodium chloride solution up to the neck of the flask, mix well, and allow the layers to separate. Determine the composition by gas chromatography (Appendix V E). Use polyethylene succinate as the stationary phase, with a coating concentration of 10%–15%. Use nitrogen as the carrier gas at a flow rate of 30 mL/min; set the hydrogen flow rate to 30 mL/min and the air flow rate to 300 mL/min. Set the injection port temperature to 250°C, the detector temperature to 250°C, and the column temperature to 185°C. Withdraw 1–2 μL of the supernatant and inject it into a gas chromatograph; record the chromatogram. The peaks elute in the following order: palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. Calculate the peak areas using the normalization method without correction factors; the respective percentages are 8%–19%, 1%–4%, 19%–50%, 34%–62%, and 0%–2%. Water and Volatile Matter: Not more than 0.2% (Appendix VII H). Microbial Limits: Take a sample of this product and test it in accordance with the prescribed method (Appendix XI J). Per 1 mL of the test specimen, the total bacterial count shall not exceed 100 CFU, the total fungal count shall not exceed 100 CFU, and *Escherichia coli* shall not be detected.
[Storage] Protect from light; keep tightly sealed and store in a cool place.
[Chemical Composition] This product is a fixed oil obtained from the germ of *Zea mays* (maize) seeds using a hot-pressing method.
[Pharmacological Action] Pharmaceutical Excipient.