Docusate Sodium
C20H37NaO7S
![]() ![]() ![]() ![]() ![]() Butanedioic acid, sulfo-, 1,4-bis(2-ethylhexyl) ester, sodium salt. Sodium 1,4-bis(2-ethylhexyl) sulfosuccinate ![]() ![]() ![]() » Docusate Sodium contains not less than 99.0 percent and not more than 100.5 percent of C20H37NaO7S, calculated on the anhydrous basis.
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.
Identification
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.
Water, Method I
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Residue on ignition
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Heavy metals
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Limit of bis(2-ethylhexyl) maleate
Mobile phase
Prepare a filtered and degassed mixture of alcohol and water (78:22). Make adjustments if necessary (see System Suitability under Chromatography
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Standard solution
Dissolve an accurately weighed quantity of USP Bis(2-ethylhexyl) Maleate RS in alcohol, and dilute quantitatively, and stepwise if necessary, to obtain a solution having a known concentration of about 80 µg per mL.
Test solution
Transfer about 1.0 g of Docusate Sodium, accurately weighed, to a 50-mL volumetric flask, dissolve in and dilute with alcohol to volume, and mix. If necessary, warm the mixture using the steam bath to achieve a complete dissolution.
Chromatographic system (see Chromatography
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Procedure
Separately inject equal volumes (about 3 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the bis(2-ethylhexyl) maleate peaks. Calculate the percentage of bis(2-ethylhexyl) maleate in the portion of Docusate Sodium taken by the formula:
5C/W(rU / rS)
in which C is the concentration, in µg per mL, of USP Bis(2-ethylhexyl) Maleate RS in the Standard solution; W is the weight, in mg, of Docusate Sodium taken to prepare the Test solution; and rU and rS are the peak responses of bis(2-ethylhexyl) maleate obtained from the Test solution and the Standard solution, respectively: not more than 0.4% is found.
Assay
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.
Salt solution
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.
Procedure
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 C20H37NaO7S.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
Chromatographic Column
USP32NF27 Page 2195
Pharmacopeial Forum: Volume No. 31(3) Page 753
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.
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