Packaging and storage—
Preserve in single-dose or in multiple-dose containers, preferably of Type I glass.
Labeling—
The label indicates that the Injection is not to be used if its color is pinkish or darker than slightly yellow or if it contains a precipitate.
Identification—
A:
Mix 10 mL of Injection with 10 mL of 3 N hydrochloric acid, cool to 0
in an ice bath, add 5 mL of sodium nitrite solution (1 in 5), stirring gently, add 2 mL of a solution of 0.1 g of 2-naphthol in 5 mL of 1 N sodium hydroxide, and observe immediately: a bright orange-red precipitate is formed (
presence of a primary aminophenyl group).
B:
It responds to the tests for
Chloride 
191
.
C:
To about 25 mL of Injection add 1 drop of
ferric chloride TS: the solution immediately turns a light green and changes to a light blue within 1 minute. Add 2 drops of 3 N hydrochloric acid: the color reverts to light green (
presence of levonordefrin).
Other requirements—
It meets the requirements under
Injections 1.
Assay for procaine hydrochloride—
Transfer 25.0 mL of Injection to a 250-mL beaker, add 10 mL of dilute hydrochloric acid (1 in 2), 15 mL of water, and 1.0 mL of formaldehyde solution, and allow to stand for 3 minutes. Titrate with 0.1
M sodium nitrite VS, using starch iodide paper as an external indicator. Perform a blank determination, and make any necessary correction. Calculate the quantity, in mg, of C
13H
20N
2O
2·HCl in each mL of the Injection taken by the formula:
(272.78 / 25)(
V2M2 
0.5
V1M1),
in which
V2 is the volume, in mL, and
M2 is the exact molarity of the 0.1
M sodium nitrite solution used in the titration,
V1 and
M1 are as defined under
Assay for tetracaine hydrochloride, and 272.78 is the molecular weight of procaine hydrochloride.
Assay for tetracaine hydrochloride—
Transfer 50.0 mL of Injection to a 100-mL beaker, add 5 g of sodium acetate and 5 mL of isopropyl alcohol, and stir until the sodium acetate is dissolved. Add 1.5 mL of potassium thiocyanate solution (75 in 100), and stir while cooling in an ice bath. Keep in the ice bath for 1 hour, stirring about four times during the period. Do not stir excessively. Prepare a filtering crucible with double suitable filter paper, connect to a suction flask, and moisten the paper with a few drops of the clear supernatant. Remove the excess liquid by suction. Filter the mixture, and dry by suction. Transfer the entire contents of the crucible to the original beaker, and rinse the crucible with 10 mL of dilute hydrochloric acid (1 in 2), followed by 30 mL of water. Transfer the rinsings to the beaker. Cool in ice, and titrate with 0.02
M sodium nitrite VS, using starch iodide paper as an external indicator. Perform a blank determination, using 10 mL of dilute hydrochloric acid (1 in 2) and 30 mL of water, and make any necessary correction. Calculate the quantity, in mg, of C
15H
24N
2O
2·HCl in each mL of the Injection taken by the formula:
(300.83 / 50)(V1M1),
in which
V1 is the volume, in mL, and
M1 is the exact molarity of the 0.02
M sodium nitrite used in the titration, and 300.83 is the molecular weight of tetracaine hydrochloride.
Assay for levonordefrin—
Ferro-citrate solution, Buffer solution, and Standard preparation—
Prepare as directed under
Epinephrine Assay 391.
Procedure—
Proceed as directed for
Procedure under
Epinephrine Assay 391. Calculate the quantity, in mg, of levonordefrin (C
9H
13NO
3) in each mL of the Injection taken by the formula:
(183.21 / 333.30)(0.05C / V)(AU / AS),
in which 183.21 and 333.30 are the molecular weights of levonordefrin and epinephrine bitartrate, respectively,
C is the concentration, in µg per mL, of
USP Epinephrine Bitartrate RS in the
Standard preparation, and
V is the volume, in mL, of Injection taken.
