Identification—
C:
The chromatogram of the
Assay preparation obtained as directed in the
Assay for epinephrine exhibits a major peak for epinephrine, the retention time of which corresponds to that exhibited in the chromatogram of the
Standard preparation obtained as directed in the
Assay for epinephrine.
Assay for prilocaine hydrochloride—
Assay preparation—
Transfer an accurately measured volume of Injection, equivalent to about 200 mg of prilocaine hydrochloride, to a 50-mL volumetric flask, dilute with Mobile phase to volume, and mix.
Procedure—
[NOTE—Use peak areas where peak responses are indicated.
] Separately inject equal volumes (about 10 µL) of the
Assay preparation and the
Standard preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the quantity, in mg, of prilocaine hydrochloride (C
13H
20N
2O·HCl) in each mL of the Injection taken by the formula:
50(C / V)(rU / rS),
in which
C is the concentration, in mg per mL, of
USP Prilocaine Hydrochloride RS in the
Standard preparation,
V is the volume, in mL, of Injection taken, and
rU and
rS are the prilocaine peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
Assay for epinephrine—
Mobile phase—
Mix 50 mL of glacial acetic acid and 930 mL of water, and adjust with 1 N sodium hydroxide to a pH of 3.40. Dissolve 1.1 g of sodium 1-heptanesulfonate in this solution, add 1.0 mL of 0.1
M disodium ethylenediaminetetraacetate, and mix. Mix about 9 volumes of this solution with 1 volume of methanol. Filter through a membrane filter (1 µm or finer porosity), and degas. Make adjustments if necessary (see
System Suitability under
Chromatography 
621
).
Standard preparation—
Dissolve an accurately weighed quantity of
USP Epinephrine Bitartrate RS in
Mobile phase to obtain a solution having a known concentration of about 9 µg of epinephrine bitartrate per mL. Pipet 10 mL of this solution into a 50-mL volumetric flask, dilute with
Mobile phase to volume, and mix to obtain a
Standard preparation having a known concentration of about 1.8 µg of epinephrine bitartrate per mL.
Assay preparation—
Transfer an accurately measured volume of Injection, equivalent to about 50 µg of epinephrine, to a 50-mL volumetric flask, dilute with Mobile phase to volume, and mix.
Chromatographic system
(see
Chromatography 621)—The liquid chromatograph is fitted with a 30-cm × 3.9-mm stainless steel column packed with packing L1, and is equipped with an electrochemical detector held at a potential of +650 mV, a controller capable of regulating the background current, and a suitable recorder, and it is operated at a temperature between 20
and 25
maintained at ±1.0
of the selected temperature. The flow rate is about 1 mL per minute. Chromatograph the
Standard preparation as directed for
Procedure: the relative standard deviation of the peak responses of successive injections of the
Standard preparation is not more than 1.5%.
Procedure—
Separately inject equal volumes (about 20 µL) of the
Assay preparation and the
Standard preparation into 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 mL of the Injection taken by the formula:
(183.21 / 333.30)50(C / V)(rU / rS),
in which 183.21 and 333.30 are the molecular weights of epinephrine and epinephrine bitartrate, respectively,
C is the concentration, in µg per mL, of
USP Epinephrine Bitartrate RS in the
Standard preparation,
V is the volume, in mL, of Injection taken, and
rU and
rS are the peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
