Butanedioic acid, sulfo-, 1,4-bis(2-ethylhexyl) ester, sodium salt.
Sodium 1,4-bis(2-ethylhexyl) sulfosuccinate
Packaging and storage
Preserve in well-closed containers.
Clarity of solution
Dissolve 25 g in 100 mL of alcohol: the solution does not develop a haze within 24 hours.
Place a small piece of it on a salt plate, add 1 drop of acetone, and promptly cover with another salt plate. Rub the plates together to dissolve the specimen, slide the plates apart, and allow the acetone to evaporate: the IR absorption spectrum of the film so obtained exhibits maxima only at the same wavelengths as that of a similar preparation of USP Docusate Sodium RS
Heavy metals 231
Transfer 2.0 g to a platinum crucible, and ignite until free from carbon. Cool, moisten the residue with 1 mL of hydrochloric acid, and evaporate on a steam bath to dryness. Add 2 mL of 6 N acetic acid, digest on a steam bath for 5 minutes, filter into one of a pair of matched 50-mL color-comparison tubes, and wash the residue with sufficient water to make 25 mL: the limit is 0.001%.
Limit of bis(2-ethylhexyl)maleate
Place 12.5 g of Docusate Sodium, previously dried at 105
for 2 hours and accurately weighed, in a 100-mL volumetric flask. Pipet 20 mL of pH 10 alkaline borate buffer (see under Solutions
in the section Reagents, Indicators, and Solutions
) into the flask, and add about 70 mL of alcohol. Swirl the flask and contents, with gentle warming, until the solid dissolves. Cool, and add alcohol to volume. Transfer a portion of this test solution to a polarographic cell that is immersed in a water bath regulated at 25 ± 0.5
, and deaerate by bubbling through the solution, for 10 minutes, purified nitrogen that previously has been passed through a solution prepared by mixing 4 volumes of alcohol and 1 volume of water. Insert the dropping mercury electrode of a suitable polarograph, and record the polarogram from
0.5 volt to
1.6 volts, using a saturated calomel electrode as the reference electrode (see Polarography 801
). Determine the height of the diffusion current at the current plateau at about
1.45 volts. To a separate 50-mL portion of the solution add 25 mg of USP Bis(2-ethylhexyl)maleate RS, accurately weighed, and when solution is complete, deaerate a portion of the resulting solution, and record the polarogram, as directed in the foregoing. The diffusion current for the test solution of Docusate Sodium is not greater than one-half the diffusion current of the solution containing the added USP Bis(2-ethylhexyl)maleate RS [not more than 0.4% of bis(2-ethylhexyl) maleate].
Tetra-n-butylammonium iodide solution
Transfer 1.250 g of tetra-n-butylammonium iodide to a 500-mL volumetric flask, dilute with water to volume, and mix.
Transfer 100 g of anhydrous sodium sulfate and 10 g of sodium carbonate to a 400-mL beaker, and add water to dissolve the two salts. Transfer the solution to a 1000-mL volumetric flask, dilute with water to volume, and mix.
Dissolve about 50 mg of Docusate Sodium, accurately weighed, in 50 mL of chloroform in a glass-stoppered, 250-mL conical flask. Add 50 mL of Salt solution
and 0.5 mL of bromophenol blue TS
, and mix. Titrate with Tetra-n-butylammonium iodide solution
until about 1 mL from the endpoint, and shake the stoppered flask vigorously for about 2 minutes. Continue the titration in 2-drop increments, shaking vigorously for about 10 seconds after each addition, and then allow the flask to stand about 10 seconds. Continue the titration until the chloroform layer just assumes a blue color. Each mL of Tetra-n-butylammonium iodide solution
is equivalent to 3.009 mg of C20
: Elena Gonikberg, Ph.D., Scientist
Expert Committee : (MDGRE05) Monograph Development-Gastrointestinal Renal and Endocrine
USP29NF24 Page 749
: Volume No. 31(3) Page 753
Phone Number : 1-301-816-8251