A: Infrared Absorption á197Kñ.

B: To 0.5mLof a solution of buprenorphine hydrochloride in methanol containing 50mg per mLadd 0.2mLof a freshly prepared solution (1in 10)of potassium ferricyanide TSand 0.5mLof ferric chloride TS:a blue color appears immediately.

C: Asolution (1in 100)meets the requirements of the tests for Chloride á191ñ.

Test solution: 20mg per mL,in methanol.

Mobile phase— Prepare a filtered and degassed mixture of methanol,1%solution of ammonium acetate,and glacial acetic acid (60:10:0.01).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard solution— Dissolve accurately weighed quantities of USP Buprenorphine Hydrochloride RSand USP Buprenorphine Related Compound A RSin Mobile phaseto obtain a solution having a known concentration of 12.5µg of each Reference Standard per mL.

Test solution— Dissolve an accurately weighed quantity of about 50mg of Buprenorphine Hydrochloride in 10.0mLof Mobile phaseto obtain a solution having a concentration of about 5mg per mL.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 288-nm detector and a 4.6-mm ×25-cm column containing packing L1.The flow rate is about 1mLper minute.The column temperature is maintained at 40.Chromatograph the Standard solution,and record the peak responses as directed for Procedure:the resolution,R,between buprenorphine hydrochloride and buprenorphine related compound Ais not less than 3.0;the column efficiency is not less than 6500theoretical plates;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20µL)of the Standard solutionand the Test solutioninto the chromatograph,and allow the Test solutionto elute for not less than two times the retention time of buprenorphine hydrochloride.Record the chromatograms,and measure the areas for the major peaks.Calculate the percentage of each impurity in the portion of Buprenorphine Hydrochloride taken by the formula: in which riis the peak response for each impurity obtained from the Test solution;rSis the peak response of buprenorphine hydrochloride obtained from the Standard solution;CSis the concentration,in mg per mL,of USP Buprenorphine Hydrochloride RSin the Standard solution;and CTis the concentration,in mg per mL,of Buprenorphine Hydrochloride in the Test solution:not more than 0.25%of any individual impurity is found,and the sum of all impurities is not more than 0.65%.