Packaging and storage—
Preserve in well-closed containers.
Identification—
A:
Dissolve 1g of sodium borate in 100mLof water,add 25drops of phenolphthalein TS,and mix.To a test tube containing 0.5mLof this solution add 2drops of 1Suppository that has been melted:the pink solution becomes colorless,and when it is heated the pink color reappears.
B:
Disperse 12Suppositories in about 125mLof water in a 250-mLbeaker on a hot plate.Cool,add 1.5mLof hydrochloric acid,and pour the mixture into a 250-mLseparator.Extract with 75mLof hexanes,discarding the lower aqueous layer and collecting the organic layer in a beaker.Evaporate with the aid of a steam bath to near dryness:the IRabsorption spectrum of a mineral oil dispersion of the residue so obtained exhibits maxima only at the same wavelengths as those of a mineral oil dispersion of
USP Stearic Acid RS.
Assay—
Transfer an accurately weighed quantity of Suppositories,equivalent to about 250mg of glycerin,to a 250-mLvolumetric flask.Dissolve in water,dilute with water to volume,and mix.Pipet 5mLof this solution into a 250-mLconical flask,and add 50.0mLof a reagent prepared by mixing 40mLof dilute sulfuric acid (1in 20)with 60mLof potassium periodate solution (1in 1000)acidified with 3to 5drops of sulfuric acid.Heat the solution on a steam bath for 15minutes,cool to room temperature,and add 1g of potassium iodide.Allow the flask to stand for 5minutes,and titrate with 0.02Nsodium thiosulfate VS,adding 3mLof starch TSas the endpoint is approached.Perform a blank determination,using water in place of Suppositories,and note the difference in volumes required.Each mLof the difference in volume of 0.02Nsodium thiosulfate consumed is equivalent to 0.4604mg of glycerin (C3H8O3).