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 á841ñ:
between 0.845and 0.905.
Viscosity á911ñ—
It has a kinematic viscosity of not less than 34.5centistokes at 40.0
.
.
Neutrality—
Boil 10mLwith an equal volume of alcohol:the alcohol remains neutral to moistened litmus paper.
Readily carbonizable substances—
Place 5mLin a glass-stoppered test tube that previously has been rinsed with chromic acid cleansing mixture (see Cleaning Glass Apparatus á1051ñ),then rinsed with water,and dried.Add 5mLof sulfuric acid containing from 94.5%to 94.9%of H2SO4,and heat in a boiling water bath for 10minutes.After the test tube has been in the bath for 30seconds,remove it quickly,and,while holding the stopper in place,give three vigorous,vertical shakes over an amplitude of about 5inches.Repeat every 30seconds.Do not keep the test tube out of the bath longer than 3seconds for each shaking period.At the end of 10minutes 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 3mLof ferric chloride CS,1.5mLof cobaltous chloride CS,and 0.5mLof cupric sulfate CS,this mixture being overlaid with 5mLof Oil (see Readily Carbonizable Substances Test á271ñ).
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 7.0µg per mL.Determine the absorbance of this solution in a 1-cm cell at the wavelength of maximum absorbance at about 275nm,using isooctane as the blank.
Procedure—
Transfer 25.0mLof Mineral Oil and 25mLof n-hexane to a 125-mLseparator,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 5.0mLof Dimethyl sulfoxide,and shake the mixture vigorously for 1minute.Allow to stand until the lower layer is clear,transfer the lower layer to another 125-mLseparator,add 2mLof n-hexane,and shake vigorously.Separate the lower layer,and determine its absorbance in a 1-cm cell,in the range of 260nm to 350nm,using as the blank Dimethyl sulfoxidethat previously has been shaken vigorously for 1minute with n-hexane in the ratio of 5mLof Dimethyl sulfoxideand 25mLof n-hexane.The absorbance at any wavelength in the specified range is not greater than one-third of the absorbance,at 275nm,of the Standard solution.
Solid paraffin—
Fill a tall,cylindrical,standard oil-sample bottle of colorless glass of about 120-mLcapacity with Mineral Oil that has been dried previously in a beaker at 105for 2hours 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 4hours:the test specimen is sufficiently clear that a black line 0.5mm in width,on a white background,held vertically behind the bottle,is clearly visible.
for 2hours 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 4hours:the test specimen is sufficiently clear that a black line 0.5mm in width,on a white background,held vertically behind the bottle,is clearly visible.
Auxiliary Information—
Staff Liaison:Catherine Sheehan,B.Sc.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 1297
Phone Number:1-301-816-8262