Tetracaine Hydrochloride

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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C₁₅H₂₄N₂O₂ · HCl 300.82

Benzoic acid, 4-(butylamino)-, 2-(dimethylamino)ethyl ester, monohydrochloride;

2-(Dimethylamino)ethyl p-(butylamino)benzoate monohydrochloride CAS RN®: 136-47-0; UNII: 5NF5D4OPCI.

1 DEFINITION

Tetracaine Hydrochloride contains NLT 98.0% and NMT 102.0% of tetracaine hydrochloride (C₁₅H₂₄N₂O₂ · HCl), calculated on the anhydrous basis.

2 IDENTIFICATION

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K

B. Identification Tests—General, Chloride〈191〉

Sample solution: 20 mg/mL

Acceptance criteria: Meets the requirements

C. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

Procedure

Prepare the standard solutions and sample solutions immediately before use, or store them at a temperature of 2°–8°. Protect them from light.

Buffer: 1.36 g/L of monobasic potassium phosphate in water prepared as follows. Dissolve 1.36 g of monobasic potassium phosphate in about 600 mL water, and add 0.5 mL of phosphoric acid. Dilute with water to 1 L.

Mobile phase: See Table 1.

Table 1

Diluent: Acetonitrile and water (20:80)

Standard stock solution: 0.4 mg/mL of USP Tetracaine Hydrochloride RS in Diluent. Sonicate for 5 min.

Standard solution: 0.04 mg/mL of USP Tetracaine Hydrochloride RS from the Standard stock solution in Diluent

Sample stock solution: 0.4 mg/mL of Tetracaine Hydrochloride in Diluent. Sonicate for 5 min.

Sample solution: 0.04 mg/mL of Tetracaine Hydrochloride from the Sample stock solution in Diluent

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 300 nm

Column: 4.6-mm × 15-cm; 5-μm packing L1

Temperatures

Column: 30°

Autosampler: 4°

Flow rate: 1.5 mL/min

Injection volume: 10 μL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 1.5

Relative standard deviation: NMT 0.73%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of tetracaine hydrochloride (C₁₅H₂₄N₂O₂ · HCl) in the portion of Tetracaine Hydrochloride taken:

Result = (r_U /r_S ) × (C_S /C_U) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Tetracaine Hydrochloride RS in the Standard solution (mg/mL)

C_U = concentration of Tetracaine Hydrochloride in the Sample solution (mg/mL)

Acceptance criteria: 98.0%–102.0% on the anhydrous basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.1%

Change to read:

Organic Impurities

Buffer, Mobile phase, Diluent, and Chromatographic system: Proceed as directed in the Assay.

Standard solution: 0.004 mg/mL each of USP Tetracaine Hydrochloride RS, USP Tetracaine Related Compound B RS, USP Tetracaine Related

Compound C RS, and USP Aminobenzoic Acid RS in Diluent

Sample solution: 1 mg/mL of Tetracaine Hydrochloride in Diluent

System suitability

Sample: Standard solution

[Note—See Table 2 for the relative retention times.]

Suitability requirements

Resolution: NLT 5.0 between tetracaine and tetracaine related compound B

Relative standard deviation: NMT 5.0% for tetracaine hydrochloride

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of aminobenzoic acid, tetracaine related compound B, and tetracaine related compound C in the portion of

Tetracaine Hydrochloride taken:

Result = (r_U /r_S ) × (C_S /C_U) × 100

r_U = peak response of corresponding tetracaine related compound from the Sample solution

r_S = peak response of corresponding tetracaine related compound from the Standard solution

C_S = concentration of corresponding tetracaine related compound in the Standard solution (mg/mL)

C_U = concentration of Tetracaine Hydrochloride in the Sample solution (mg/mL)

Calculate the percentage of each unspecified impurity in the portion of Tetracaine Hydrochloride taken:

Result = (r_U /r_S ) × (C_S /C_U) × 100

r_U = peak response of each unspecified impurity from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Tetracaine Hydrochloride RS in the Standard solution (mg/mL)

C_U = concentration of Tetracaine Hydrochloride in the Sample solution (mg/mL)

Acceptance criteria: See Table 2. Disregard any impurity peaks less than 0.05%.

Table 2

^a 4-Aminobenzoic acid.

5 SPECIFIC TESTS

Water Determination, Method I〈921〉: NMT 2.0%

Sterility Tests 〈71〉: Where the label states that Tetracaine Hydrochloride is sterile, it meets the requirements.

Bacterial Endotoxins Test 〈85〉: Where the label states that Tetracaine Hydrochloride is sterile or must be subjected to further processing during the preparation of injectable or other sterile dosage forms, it contains NMT 0.7 USP Endotoxin Units/mg of tetracaine hydrochloride.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

Labeling: Where it is intended for use in preparing injectable dosage forms, the label states that it is sterile or must be subjected to further

processing during the preparation of injectable or other sterile dosage forms.

USP Reference Standards 〈11〉

USP Aminobenzoic Acid RS

USP Tetracaine Hydrochloride RS

USP Tetracaine Related Compound B RS

4-(Butylamino)benzoic acid.

C₁₁H₁₅NO₂ 193.24

USP Tetracaine Related Compound C RS

Methyl 4-(butylamino)benzoate.

C₁₂H₁₇NO₂ 207.35