Identification
A:
It responds to the Identificationtests under Bupivacaine Hydrochloride Injection.
B:
Pipet a volume of Injection,equivalent to about 50µg of epinephrine,into a suitable container,add 0.1mLof
Ferro-citrate solutionand 2.0mLof
Buffer solution(prepared as directed under
Epinephrine Assay á391ñ),mix,and allow the solution to stand for 10minutes.Filter the solution:the filtrate is violet in color and may turn brownish.
Assay for bupivacaine hydrochloride
Assay preparation
Transfer an accurately measured volume of Injection,equivalent to about 50mg of bupivacaine hydrochloride,to a 100-mLvolumetric flask,add 10.0mLof Internal standard solution,dilute with methanol to volume,and mix.
Assay for epinephrine
Mobile phase
Prepare a suitably filtered and degassed mixture of water,methanol,and 2
Mmonobasic sodium phosphate (900:50:50),containing in each 1000mL,40mg of edetate disodium,0.4mLof phosphoric acid,and 0.4g of sodium 1-octanesulfonate.Make adjustments,if necessary,to obtain a retention time of not less than 11minutes for the epinephrine peak (see
System Suitabilityunder
Chromatography á621ñ).
Standard preparation
Dissolve an accurately weighed quantity of
USP Epinephrine Bitartrate RSin
Mobile phaseto obtain a solution having a concentration of about 2µg per mL.
Resolution solution
Dissolve suitable quantities of epinephrine bitartrate and dopamine hydrochloride in Mobile phaseto obtain a solution containing about 2µg of each per mL.
Assay preparation
Transfer an accurately measured volume of Injection,equivalent to about 25µg of epinephrine,to a 25-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.
Chromatographic system
(see
Chromatography á621ñ)The liquid chromatograph is equipped with an electrochemical detector held at a potential of +0.75volt and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1.2mLper minute.Chromatograph the
Resolution solution,and record the peak responses as directed for
Procedure:the resolution,
R,between the epinephrine and dopamine peaks is not less than 6.0;and the relative retention times are about 2for dopamine and 1.0for epinephrine.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Separately inject equal volumes (about 20µL)of the
Standard preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in µg,of epinephrine (C
9H
13NO
3)in each mLof the Injection taken by the formula:
(183.21/333.30)(25)(C/V)(rU/rS),
in which 183.21and 333.30are the molecular weights of epinephrine and epinephrine bitartrate,respectively;
Cis the concentration,in µg per mL,of
USP Epinephrine Bitartrate RSin the
Standard preparation;Vis the volume,in mL,of Injection taken;and
rUand
rSare the peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.