Medium: 0.1Nhydrochloric acid;900mL.

Apparatus 1: 100rpm.

Time: 30minutes.

Dilute hydrochloric acid— Dilute 37mLof hydrochloric acid with water to one liter.

Ammonium sulfamate reagent— Dissolve 250mg of ammonium sulfamate in 100mLofDilute hydrochloric acid.

N-(1-Naphthyl)ethylenediamine dihydrochloride reagent— Dissolve 100mg of N-(1-naphthyl)ethylenediamine dihydrochloride in 100mLof Dilute hydrochloric acid.

Sulfanilamide-mercuric chloride reagent— Dissolve 100mg of sulfanilamide and 100mg of mercuric chloride in 100mLofDilute hydrochloric acid.

Sodium nitrite reagent— Dissolve 200mg of sodium nitrite in 100mLof dilute sulfuric acid (1in 50).Prepare fresh.

Standard preparation— Dissolve an accurately weighed quantity of USP Penicillamine RSin 0.1Nhydrochloric acid to obtain a solution having a known concentration of about 250µg per mL.

Procedure— Pipet an aliquot of the filtered test solution,estimated to contain about 278µg of penicillamine,into a 100-mLvolumetric flask.Into a similar flask pipet an equivalent volume of 0.1Nhydrochloric acid to provide a reagent blank,and into a third 100-mLvolumetric flask pipet 1mLofStandard preparation.Treat each flask as follows.Add by pipet 3mLofSodium nitrite reagent,and mix by swirling occasionally.After 5minutes,add 10mLofAmmonium sulfamate reagent,swirl,and allow to stand for an additional 5minutes.Add 5mLofSulfanilamide-mercuric chloride reagent,swirl,and immediately add 10mLofN-(1-Naphthyl)ethylenediamine dihydrochloride reagent.Dilute with water to volume,and mix.Determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 540nm,with a suitable spectrophotometer,against the reagent blank.Calculate the percentage dissolution of the Capsule taken by the formula: in which Cis the concentration,in µg per mL,of USP Penicillamine RSin theStandard preparation;Wis the labeled quantity,in mg,of penicillamine in the Capsule;Vis the volume,in mL,of the aliquot of test solution used;and AUand ASare the absorbances of the solutions from the test solution and theStandard preparation,respectively.

Tolerances— Not less than 80%(Q)of the labeled amount of C5H11NO2Sis dissolved in 30minutes.

Diluent,Mobile phase,and Resolution solution— Proceed as directed in theAssay underPenicillamine.

Standard preparation— Dissolve an accurately weighed quantity of USP Penicillamine Disulfide RSinDiluent to obtain a solution having a known concentration of about 0.025mg per mL.

Test preparation— Use theAssay preparation.

Chromatographic system— Proceed as directed in theAssay underPenicillamine.Chromatograph theStandard preparation,and record the penicillamine disulfide peak responses as directed forProcedure:the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— [NOTE—Use peak areas where peak responses are indicated.]Separately inject equal volumes (about 20µL)of theStandard preparation and theTest preparation into the chromatograph,record the chromatograms,and measure the responses for the penicillamine disulfide peaks.Calculate the percentage of penicillamine disulfide (C10H20N2O4S2)in the Capsules taken by the formula: in which Cis the concentration,in mg per mL,of USP Penicillamine Disulfide RSin theStandard preparation;Lis the quantity,in mg,of penicillamine in each Capsule based on the labeled amount;Vis the volume,in mL,of the volumetric flask used to prepare theAssay preparation in theAssay;Nis the number of Capsules used to prepare theAssay preparation in theAssay;and rUand rSare the penicillamine disulfide peak responses obtained from theTest preparation and theStandard preparation,respectively:not more than 2.0%of penicillamine disulfide is found.

Diluent,Mobile phase,Resolution solution,Standard preparation,and Chromatographic system— Proceed as directed in theAssay underPenicillamine.

Assay preparation— Carefully open and transfer the contents of not fewer than 10Capsules,accurately counted,to a suitable volumetric flask of such volume that when treated as described below,a solution is obtained that contains about 1.25mg of penicillamine per mL.Add the empty Capsule shells to the flask,and add sufficientDiluent to the flask to fill it to about three-fourths of its capacity.Shake for 1minute,and allow the mixture to stand for 90minutes.Dilute withDiluent to volume,and mix.Filter a portion of this solution through a suitable filter of 1µm or finer porosity,and use the clear filtrate as theAssay preparation.

Procedure— Proceed as directed forProcedure in theAssay underPenicillamine.Calculate the quantity,in mg,of penicillamine (C5H11NO2S)in each Capsule taken by the formula: in which Cis the concentration,in mg per mL,of USP Penicillamine RSin theStandard preparation;Vis the volume,in mL,of the volumetric flask used to prepare theAssay preparation;Nis the number of Capsules used to prepare theAssay preparation;and rUand rSare the penicillamine peak responses obtained from theAssay preparation and theStandard preparation,respectively.