Medium: water;500mL.

Apparatus 2: 50rpm.

Time: 30minutes.

pH8.2buffer— Prepare as directed under Assay.

Copper sulfate reagent— Mix 10mLof copper sulfate solution (5g copper sulfate pentahydrate in 100mLof water)with 40mLof pH8.2buffer.[NOTE—The solution must be clear.]

Standard preparation— Dissolve an accurately weighed quantity of USP Trientine Hydrochloride RSin water to obtain a solution having a known concentration of about 0.5mg per mL.

Procedure— Pipet an aliquot of a filtered portion of the solution under test,estimated to contain about 5mg of trientine hydrochloride,into a 50-mLcentrifuge tube.Into a similar centrifuge tube,pipet an equivalent volume of water to provide a reagent blank,and into a third centrifuge tube pipet 10mLof Standard preparation.Into each tube,pipet 5mLof Copper sulfate reagent,stopper,and mix immediately using a vortex mixer.Determine the absorbances of the solutions from the Standard preparationand the test solution at 580and 410nm,with a suitable spectrophotometer,against the reagent blank.Calculate the quantity in mg of trientine hydrochloride dissolved by the formula: in which Cis the concentration,in mg per mL,of USP Trientine Hydrochloride RSin the Standard preparation,Vis the volume,in mL,of the aliquot of test solution used,AUand ASare the absorbances at 580nm of test and standard solutions,respectively,and AUXand ASXare the absorbances at 410nm of test and standard solutions,respectively.

Tolerances— Not less than 80%(Q)of the labeled amount of C6H18N4·2HCl is dissolved in 30minutes.

Copper reagent— Dissolve 5g of copper sulfate pentahydrate in water to make 100mL,and mix.

pH8.2buffer— Dissolve 20.74g of anhydrous dibasic sodium phosphate,6.72g of anhydrous citric acid,and 0.535g of monobasic sodium phosphate in 400mLof water,adjust with sodium hydroxide solution (1in 2)to a pHof 8.2±0.05,dilute with water to make 500mL,and mix.

Standard preparation— Dissolve an accurately weighed quantity of USP Trientine Hydrochloride RSin methanol to obtain a solution having a known concentration of about 2.5mg per mL.Transfer 5.0mLof this solution to a glass-stoppered,50-mLconical flask.

Assay preparation— Remove,as completely as possible,the contents of not less than 20Capsules.Weigh the contents,and determine the average weight per capsule.Mix the combined contents,and transfer an accurately weighed quantity of the powder,equivalent to about 250mg of trientine hydrochloride,to a 100-mLvolumetric flask.Add about 70mLof methanol,and shake or sonicate to dissolve.Dilute with methanol to volume,mix,and filter,discarding the first few mLof the filtrate.Transfer 5.0mLof this solution to a glass-stoppered,50-mLconical flask.

Procedure— To each of the flasks containing the Standard preparationand the Assay preparationand to a similar flask containing 5.0mLof methanol to provide the blank,add 10.0mLof pH8.2bufferand 1.0mLof Copper reagent,and mix.Concomitantly determine the absorbances of the solutions at the wavelength of maximum absorbance at about 580nm,with a suitable spectrophotometer,against the blank.Calculate the quantity,in mg,of C6H18N4·2HCl in the portion of Capsules taken by the formula: in which Cis the concentration,in mg per mL,of USP Trientine Hydrochloride RSin the Standard preparation,and AUand ASare the absorbances of the solutions from the Assay preparationand the Standard preparation,respectively.