A: The retention time of the oxycodone peak in the chromatogram of the Assay preparationcorresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.

B: Thin-Layer Chromatographic Identification Test á201ñ—

Test solution— Transfer a portion of powdered Tablets,equivalent to about 5mg of oxycodone hydrochloride,to a suitable screw-capped tube,add 5mLof chloroform,sonicate for about 30seconds,shake for several minutes,and centrifuge.Use the clear supernatant.

Standard solution: 0.9mg of USP Oxycodone RSper mLof chloroform.

Application volume: 20µL.

Developing solvent system: a mixture of acetone,toluene,ether,and ammonium hydroxide (6:4:1:0.3).

Procedure— Proceed as directed in the chapter.Spray with iodoplatinate TS:the RFvalue,color,and size of the principal spot obtained from the Test solutioncorrespond to those obtained from the Standard solution;and no other spot is observed.

Medium: water;500mL.

Apparatus 2: 50rpm.

Time: 45minutes.

Procedure— Determine the amount of C18H21NO4·HCl dissolved by employing UVabsorption at about 225nm on filtered portions of the solution under test,suitably diluted with Dissolution Medium,if necessary,in comparison with a Standard solution having a known concentration of USP Oxycodone RSin 0.1Nhydrochloric acid.

Tolerances— Not less than 70%(Q)of the labeled amount of C18H21NO4·HCl is dissolved in 45minutes.

Mobile phase— Prepare a suitable mixture of 0.01Msodium 1-heptanesulfonate,acetonitrile,and glacial acetic acid (74:25:1).Adjust this mixture with 5Nsodium hydroxide to a pHof 3.5.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).Filter and degas this solution before use.

Standard preparation— Dissolve an accurately weighed quantity of USP Oxycodone RSquantitatively in Mobile phaseto obtain a solution having a known concentration of about 0.045mg per mL.

Assay preparation— Weigh and finely powder not less than 20Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 5mg of oxycodone hydrochloride,to a 100-mLvolumetric flask,add about 50mLof Mobile phase,sonicate for about 5minutes,and shake by mechanical means for about 15minutes.Dilute with Mobile phaseto volume,and mix.Filter a portion of this mixture through a filter having a porosity of 0.5µm or finer,and use the clear filtrate as the Assay preparation.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm ×15-cm column that contains 5-µm packing L1.The flow rate is about 1.7mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the tailing factor for the oxycodone peak is not more than 2.0,and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 10µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses of the oxycodone peaks.Calculate the quantity,in mg,of oxycodone hydrochloride (C18H21NO4·HCl)in the portion of Tablets taken by the formula: in which 351.82and 315.37are the molecular weights of oxycodone hydrochloride and oxycodone base,respectively,Cis the concentration,in mg per mL,of USP Oxycodone RSin the Standard preparation,and rUand rSare the oxycodone peak responses obtained from the Assay preparationand the Standard preparation,respectively.