U.S. PHARMACOPEIA

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Mineral Oil
» Mineral Oil is a mixture of liquid hydrocarbons obtained from petroleum. It may contain a suitable stabilizer.
Packaging and storage— Preserve in tight containers.
Labeling— Label it to indicate the name of any substance added as a stabilizer.
Specific gravity 841: between 0.845 and 0.905.
Viscosity 911— It has a kinematic viscosity of not less than 34.5 centistokes at 40.0.
Neutrality— Boil 10 mL with an equal volume of alcohol: the alcohol remains neutral to moistened litmus paper.
Readily carbonizable substances— Place 5 mL in a glass-stoppered test tube that previously has been rinsed with chromic acid cleansing mixture (see Cleaning Glass Apparatus 1051), then rinsed with water, and dried. Add 5 mL of sulfuric acid containing from 94.5% to 94.9% of H2SO4, and heat in a boiling water bath for 10 minutes. After the test tube has been in the bath for 30 seconds, remove it quickly, and, while holding the stopper in place, give three vigorous, vertical shakes over an amplitude of about 5 inches. Repeat every 30 seconds. Do not keep the test tube out of the bath longer than 3 seconds for each shaking period. At the end of 10 minutes from the time when first placed in the water bath, remove the test tube: the Oil may turn hazy, but it remains colorless, or shows a slight pink or yellow color, and the acid does not become darker than the standard color produced by mixing in a similar test tube 3 mL of ferric chloride CS, 1.5 mL of cobaltous chloride CS, and 0.5 mL of cupric sulfate CS, this mixture being overlaid with 5 mL of Oil (see Readily Carbonizable Substances Test 271).
Limit of polynuclear compounds—
Dimethyl sulfoxide— Use spectrophotometric grade dimethyl sulfoxide.
Standard solution— Dissolve a quantity of naphthalene, accurately weighed, in isooctane, and dilute quantitatively and stepwise with isooctane to obtain a solution having a concentration of 7.0 µg per mL. Determine the absorbance of this solution in a 1-cm cell at the wavelength of maximum absorbance at about 275 nm, using isooctane as the blank.
Procedure— Transfer 25.0 mL of Mineral Oil and 25 mL of n-hexane to a 125-mL separator, and mix. [NOTE—Use only n-hexane that previously has been washed by being shaken twice with one-fifth its volume of Dimethyl sulfoxide. Use no lubricants other than water on the stopcock, or use a separator equipped with a suitable polymeric stopcock.] Add 5.0 mL of Dimethyl sulfoxide, and shake the mixture vigorously for 1 minute. Allow to stand until the lower layer is clear, transfer the lower layer to another 125-mL separator, add 2 mL of n-hexane, and shake vigorously. Separate the lower layer, and determine its absorbance in a 1-cm cell, in the range of 260 nm to 350 nm, using as the blank Dimethyl sulfoxide that previously has been shaken vigorously for 1 minute with n-hexane in the ratio of 5 mL of Dimethyl sulfoxide and 25 mL of n-hexane. The absorbance at any wavelength in the specified range is not greater than one-third of the absorbance, at 275 nm, of the Standard solution.
Solid paraffin— Fill a tall, cylindrical, standard oil-sample bottle of colorless glass of about 120-mL capacity with Mineral Oil that has been dried previously in a beaker at 105 for 2 hours and cooled to room temperature in a desiccator over silica gel. Insert the stopper, and immerse the bottle in a mixture of ice and water for 4 hours: the test specimen is sufficiently clear that a black line 0.5 mm in width, on a white background, held vertically behind the bottle, is clearly visible.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Auxiliary Information— Staff Liaison : Hong Wang, Ph.D. , Senior Scientific Associate
Expert Committee : (EM205) Excipient Monographs 2
USP29–NF24 Page 1437
Phone Number : 1-301-816-8351