A: Ash the contents of 1Capsule,dissolve the residue in 10mLof dilute hydrochloric acid (1in 12),and filter:the filtrate responds to the tests for Calcium á191ñ.

B: Empty the contents of 1Capsule into a conical flask,add isopropyl alcohol to obtain a concentration of 10mg of docusate calcium per mL,and mix.This solution responds to Identificationtest Cunder Docusate Calcium.

Medium: water;500mL.

Apparatus 2: 50rpm.

Time: 15minutes.

Procedure— Place 1Capsule in each vessel,and allow the Capsule to sink to the bottom of the vessel before starting rotation of the blade.Observe the Capsules,and record the time taken for each capsule shell to rupture.

Tolerances— The requirements are met if all of the Capsules tested rupture in not more than 15minutes.If 1or 2of the Capsules rupture in more than 15but not more than 30minutes,repeat the test on 12additional Capsules.Not more than 2of the total of 18Capsules tested rupture in more than 15but not more than 30minutes.

SOLID-FILLED CAPSULES: meet the requirements for Content Uniformity.

SOLUTION-FILLED CAPSULES: meet the requirements for Weight Variation.

Basic fuchsin solution— Dissolve 100mg of basic fuchsin,previously recrystallized from alcohol,in 3mLof methanol in a 100-mLvolumetric flask,dilute with water to volume,and mix.Filter prior to use.

Standard preparation— Weigh accurately about 50mg of USP Docusate Calcium RSinto a 10-mLvolumetric flask,dissolve in isopropyl alcohol,dilute with isopropyl alcohol to volume,and mix.Transfer 5.0mLof this solution to a 500-mLvolumetric flask containing 90mLof a mixture of water and isopropyl alcohol (1:1)with swirling,dilute with water to volume,and mix.The concentration of USP Docusate Calcium RSin the Standard preparationis about 50µg per mL.

Assay preparation— To 10Capsules in a 400-mLbeaker add 300mLof hot water.Heat on a steam bath,with occasional stirring,until the Capsules are completely disintegrated,cool,and transfer with the aid of 100mLof warm water to a 1000-mLvolumetric flask.Rinse the beaker with 100mLof isopropyl alcohol,add the rinsing to the volumetric flask,and shake to dissolve any previously undissolved particles.Dilute with a mixture of water and isopropyl alcohol (1:1)to volume,and mix.Transfer 10.0mLof this solution to a 100-mLvolumetric flask,dilute with water to volume,and mix.

Procedure— Transfer 4.0mLof the Standard preparationto a 125-mLseparator.To a second 125-mLseparator transfer an accurately measured volume of the Assay preparation,equivalent to 200to 240µg of docusate calcium,and add a solution of isopropyl alcohol (1in 100),if necessary,to bring the volume of the solution in the separator to 4.0mL.To each separator transfer 20.0mLof pH1.2hydrochloric acid buffer (see under Solutionsin the section Reagents,Indicators,and Solutions)and 2.0mLof Basic fuchsin solution,add 20mLof chloroform to each,and shake for 1minute.Allow the phases to separate,and transfer the chloroform extracts,through separate pledgets of absorbent cotton,into separate 100-mLvolumetric flasks.Extract each of the solutions in the separators in the same manner with additional 20-mLportions of chloroform until no more color is visible in the extract,and pass each extract through the pledget of cotton used for the preceding extract into the flask containing the preceding extract.Dilute the contents of each flask to volume by passing chloroform through the cotton pledgets that had been used to filter the extracts,and mix.Concomitantly determine the absorbances of the solutions in 1-cm cells at the wavelength of maximum absorbance at about 545nm,with a suitable spectrophotometer,using chloroform as the blank.Calculate the quantity,in mg,of C40H74CaO14S2in each Capsule taken by the formula: in which Cis the concentration,in µg per mL,of anhydrous docusate calcium in the Standard preparation;Vis the volume,in mL,of Assay preparationtaken;and AUand ASare the absorbances of the solutions from the Assay preparationand the Standard preparation,respectively.