A: Transfer a portion of the contents of the Capsules,equivalent to about 100mg of dicyclomine hydrochloride,to a separator containing 10mLof water and 1mLof hydrochloric acid.Extract the aqueous acid solution with two 30-mLportions of chloroform,transfer the chloroform extracts to a second separator containing 20mLof water and 1mLof sodium hydroxide solution (1in 10),and shake.Filter the chloroform layer through anhydrous sodium sulfate into a suitable container,and add 3mLof a freshly prepared 1in 20solution of acetyl chloride in anhydrous methanol,prepared by cautiously adding acetyl chloride dropwise to anhydrous methanol with stirring.Evaporate under reduced pressure at room temperature until the residue has been thoroughly dried:the IRabsorption spectrum of a potassium bromide dispersion of the dicyclomine hydrochloride so obtained exhibits maxima and minima at the same wavelengths as that of a similar preparation of USP Dicyclomine Hydrochloride RS.

B: The retention time of the major peak in the chromatogram of theAssay preparationcorresponds to that in the chromatogram of theStandard preparation,as obtained in theAssay.

Medium: 0.01Nhydrochloric acid;500mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Picric acid solution— Transfer about 100mg of picric acid and 14.5g of anhydrous sodium acetate to a 500-mLvolumetric flask,and dissolve in 400mLof water.Add 20.0mLof glacial acetic acid,dilute with water to volume,and mix.

Standard solution— Prepare a solution in 0.01Nhydrochloric acid having a known concentration of about 18µg per mLof USP Dicyclomine Hydrochloride RS.

Procedure— Determine the amount of C19H35NO2·HCl dissolved using the following procedure.Pipet 20mLeach of the solution under test,theStandard solution,and 0.01Nhydrochloric acid to provide a blank,into separate suitable separators.Add 5.0mLofPicric acid solutionand 25.0mLof chloroform to each separator,and shake for 1minute.Collect the chloroform layer in a suitable vessel containing 2.0g of anhydrous sodium sulfate,shake,and allow the solutions to stand for 10minutes.Concomitantly determine the absorbances of the solutions at the wavelength of maximum absorbance at about 405nm,using the blank to set the spectrophotometer.

Tolerances— Not less than 75%(Q)of the labeled amount of C19H35NO2·HCl is dissolved in 45minutes.

0.02M Phosphate buffer,pH7.5— Dissolve 2.72g of monobasic potassium phosphate in 900mLof water,adjust with 10%sodium hydroxide to a pHof 7.5±0.1,dilute with water to 1000mL,and mix.

Mobile phase— Prepare a mixture of acetonitrile and 0.02M Phosphate buffer,pH7.5(70:30),filter,and degas.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Diluent— Prepare a mixture of acetonitrile and water (70:30).

Standard preparation— Dissolve an accurately weighed quantity of USP Dicyclomine Hydrochloride RSin Diluentto obtain a solution having a known concentration of about 0.4mg per mL.[NOTE—This solution is stable for 2days.]

Assay preparation— Remove,as completely as possible,the contents of not fewer than 20Capsules,and mix the contents.Transfer an accurately weighed portion of the powder,equivalent to about 20mg of dicyclomine hydrochloride,to a 50-mLvolumetric flask.Add 2.0mLof water,and sonicate for at least 2minutes to disperse the sample.Add 35mLof acetonitrile,sonicate for at least 5minutes,and shake by mechanical means for at least 30minutes.Add 10mLof water,allow the preparation to equilibrate to room temperature,then dilute with water to volume,and mix.Centrifuge,for at least 5minutes,a portion of this solution in a 15-mLglass centrifuge tube.Use the clear supernatant.

Chromatographic system (see Chromatography á621ñ)— The liquid chromatograph is equipped with a 215-nm detector and a 4.6-mm ×15-cm column containing 3-µm packing L7.The flow rate is about 1.0mLper minute.Chromatograph the Standard preparation,and record the responses as directed for Procedure:the tailing factor for the analyte peak is not more than 1.5;and the relative standard deviation for replicate injections is not more than 1.5%.

Procedure— Separately inject equal volumes (about 50µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of dicyclomine hydrochloride (C19H35NO2·HCl)in the portion of Capsules taken by the formula: in which Cis the concentration,in mg per mL,of USP Dicyclomine Hydrochloride RSin the Standard preparation;and rUand rSare the areas of the dicyclomine peak obtained from the Assay preparationand the Standard preparation,respectively.