Packaging and storage—
Preserve in
Containers for Sterile Solids as described under
Injections 
1
, preferably of Type I glass.
Completeness of solution 641—
A 10-mg portion dissolves in 1 mL of water in not more than 2 seconds to yield a colorless solution free from undissolved solid.
Constituted solution—
At the time of use, it meets the requirements for
Constituted Solutions under
Injections 1.
Identification—
Solution:
the solution employed for measurement of absorbance in the
Assay.
Uniformity of dosage units 905:
it meets the requirements employing the following method.
Test preparation—
Transfer the contents of one container, with the aid of water, to a 200-mL volumetric flask, add water to volume, and mix. Pipet a portion of this solution, equivalent to about 1 mg of tetracaine hydrochloride, to a 100-mL volumetric flask, add 5 mL of dilute hydrochloric acid (1 in 200) and 10 mL of
Buffer No. 6, 10 percent, pH 6.0 (see
Phosphate Buffers and Other Solutions under
Antibiotics— Microbial Assays 81), add water to volume, and mix.
Procedure—
Proceed as directed for
Procedure in the
Assay, except to use the
Test preparation instead of the
Assay preparation.
Calculate the quantity, in mg, of C15H24N2O2·HCl in each container taken by the formula:
20(C / V)(AU / AS),
in which
V is the volume, in mL, of the portion used in the
Test preparation,
AU is the absorbance of the
Test preparation, and
C and
AS are as defined in the
Assay.
pH 791:
between 5.0 and 6.0, in a solution (1 in 100).
Residue on ignition—
Weigh accurately about 500 mg, transfer to a beaker, and dissolve in 10 mL of methanol. Filter through paper previously washed with methanol, collecting the filtrate in an ignited and tared crucible and washing the beaker and the filter paper with 25 mL to 30 mL of methanol. Evaporate with the aid of heat and a current of air to dryness, and proceed as directed under
Residue on Ignition 281, beginning with “Heat, gently at first.” Not more than 0.1% of residue is found.
Chromatographic purity—
Dissolve an accurately weighed quantity of Tetracaine Hydrochloride for Injection in water to obtain a test solution containing 50 mg per mL, and proceed as directed in the test for
Chromatographic purity under
Tetracaine, beginning with “Prepare a Standard solution.”
Assay—
Assay preparation—
Transfer to a tared 20-mL beaker the contents of a sufficient number of containers of Tetracaine Hydrochloride for Injection to yield about 100 mg of tetracaine hydrochloride. Weigh immediately, and transfer with the aid of water to a 500-mL volumetric flask. Add water to volume, and mix. Transfer 5.0 mL to a 100-mL volumetric flask, add 5 mL of dilute hydrochloric acid (1 in 200) and 10 mL of
Buffer No. 6, 10 percent, pH 6.0 (see
Phosphate Buffers 81), then add water to volume, and mix.
Procedure—
Concomitantly determine the absorbances of the
Assay preparation and the
Standard preparation at the wavelength of maximum absorbance at about 310 nm, with a suitable spectrophotometer, using water as the blank. Calculate the quantity, in mg, of C
15H
24N
2O
2·HCl in the portion of Tetracaine Hydrochloride for Injection taken by the formula:
10C(AU / AS),
in which
C is the concentration, in µg per mL, of
USP Tetracaine Hydrochloride RS in the
Standard preparation, and
AU and
AS are the absorbances of the
Assay preparation and the
Standard preparation, respectively.
