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

B: Thin-Layer Chromatographic Identification Test 201—

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

Standard solution: 0.9 mg of USP Oxycodone RS per mL of chloroform.

Application volume: 20 µL.

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 RF value, color, and size of the principal spot obtained from the Test solution correspond to those obtained from the Standard solution; and no other spot is observed.

Medium: water; 500 mL.

Apparatus 2: 50 rpm.

Time: 45 minutes.

Procedure— Determine the amount of C18H21NO4·HCl dissolved by employing UV absorption at about 225 nm 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 RS in 0.1 N hydrochloric acid.

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

(Official January 1, 2007)

Mobile phase— Prepare a suitable mixture of 0.01 M sodium 1-heptanesulfonate, acetonitrile, and glacial acetic acid (74:25:1). Adjust this mixture with 5 N sodium hydroxide to a pH of 3.5. Make adjustments if necessary (see System Suitability under Chromatography 621). Filter and degas this solution before use.

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

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

Chromatographic system (see Chromatography 621)—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 1.7 mL per 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 10 µL) of the Standard preparation and the Assay preparation into 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 351.82 and 315.37 are the molecular weights of oxycodone hydrochloride and oxycodone base, respectively, C is the concentration, in mg per mL, of USP Oxycodone RS in the Standard preparation, and rU and rS are the oxycodone peak responses obtained from the Assay preparation and the Standard preparation, respectively.