Procaine Hydrochloride and Epinephrine Injection

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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1 DEFINITION

Procaine Hydrochloride and Epinephrine Injection is a sterile solution of Procaine Hydrochloride and Epinephrine Hydrochloride in Water for Injection. The content of epinephrine is NMT 0.002% (1 in 50,000). It contains NLT 95.0% and NMT 105.0% of the labeled amount of procaine hydrochloride (C₁₃H₂₀N₂O₂·HCl), and NLT 90.0% and NMT 115.0% of the labeled amount of epinephrine (C₉H₁₃NO₃).

2 IDENTIFICATION

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

Sample: Evaporate a portion of Injection, equivalent to 20 mg of procaine hydrochloride, on a steam bath just to dryness, and dry over silica gel for 18 h, protected from light. Use the residue for the test.

B.

Solution A: 100 mg/mL of sodium hydroxide in water

Solution B: 20 mg/mL of 2-naphthol in Solution A

Analysis: Dissolve 10 mg of the residue obtained in Identification A in 1 mL of water, add 1 drop each of hydrochloric acid and 100 mg/mL of sodium nitrite in water, then add 1 mL of Solution B, and shake.

Acceptance criteria: A scarlet-red precipitate is formed.

3 ASSAY

Procaine Hydrochloride

Standard solution: Transfer to a 125-mL separator about 50 mg, accurately weighed, of USP Procaine Hydrochloride RS and dissolve in 20 mL of water.

Sample solution: Transfer to a 125-mL separator an accurately measured volume of Injection, equivalent to about 50 mg of procaine hydrochloride, and dilute with water to 20 mL.

Instrumental conditions

Mode: UV

Analytical wavelength: 280 nm

Blank: Chloroform

Analysis

Samples: Standard solution and Sample solution

Add 5 mL of ammonium hydroxide, 6 N, to both the Standard solution and Sample solution, then treat each as follows. Extract with five 25-mL portions of chloroform, and filter the combined extracts through 1 g of sodium sulfate, anhydrous supported on a pledget of glass wool. Receive the filtrate in a 200-mL volumetric flask, and add chloroform to volume. Transfer 3.0 mL of this solution to a 100-mL volumetric flask, and add chloroform to volume. Concomitantly determine the absorbances of both solutions using the Blank.

Calculate the percentage of the labeled amount of procaine hydrochloride (C₁₃H₂₀N₂O₂·HCl) in the portion of Injection taken:

Result = (Aᵤ / Aₛ) × (Cₛ / Cᵤ) × 100

Aᵤ = absorbance of the Sample solution

Aₛ = absorbance of the Standard solution

Cₛ = concentration of USP Procaine Hydrochloride RS in the Standard solution (mg/mL)

Cᵤ = concentration of procaine hydrochloride in the Sample solution (mg/mL)

Acceptance criteria: 95.0%–105.0%

Content of Epinephrine

Solution A: Alcohol, 200 mg/mL of sodium hydroxide in water, and 20 mg/mL of ascorbic acid in water (25:20:2). Prepare fresh on the day of use.

Standard stock solution: 0.18 mg/mL of USP Epinephrine Bitartrate RS prepared as follows. Transfer 18 mg of USP Epinephrine Bitartrate RS to a 100-mL volumetric flask and add sodium bisulfite solution (1 in 1000) to volume.

Standard solution: 10 µg/mL of epinephrine from Standard stock solution in water

Sample solution: A portion of Injection nominally equivalent to 10 µg of epinephrine

Instrumental conditions

Mode: Fluorescence

Excitation wavelength: 420 nm

Detection wavelength: 520 nm

Blank: Water

Analysis

Samples: Standard solution and Sample solution

Pipet 1 mL of the Sample solution and Standard solution into separate 50-mL beakers. Treat the contents of each beaker as follows. Add 10 mL of dilute hydrochloric acid (1 in 120), and heat gently to reduce the volume of solution to 5 mL. Allow to cool to room temperature, then add 5 mL of sodium acetate solution (1 in 5), followed by 0.5 mL of potassium ferricyanide solution (1 in 400). At 2 min, accurately timed, after the last addition, add 20 mL of Solution A, transfer the contents to a corresponding 50-mL volumetric flask with the aid of water, and add water to volume. At 15–20 min after the addition of Solution A, determine the fluorescences of each solution and of a reagent blank.

Calculate the percentage of the labeled amount of epinephrine (C₉H₁₃NO₃) in the portion of Injection taken:

Result = [(Iᵤ − B) / (Iₛ − B)] × (Cₛ / Cᵤ)

Iᵤ = fluorescence reading of the Sample solution

B = fluorescence reading of the Blank

Iₛ = fluorescence reading of the Standard solution

Cₛ = concentration of epinephrine of USP Epinephrine Bitartrate RS in the Standard solution (µg/mL)

Cᵤ = nominal concentration of epinephrine in the Sample solution (µg/mL)

Acceptance criteria: 90.0%–115.0%

4 SPECIFIC TESTS

Color and Clarity

Standard solution: 0.1 N iodine VS and water (1:249)

Sample solution: A portion of Injection

Instrumental conditions

Mode: Vis

Analytical wavelength: 460 nm

Cell: 1 cm

Analysis

Samples: Standard solution and Sample solution

Visually examine a portion of the Sample solution in a suitable clear glass test tube against a white background: it is not pinkish and it contains no precipitate. If any yellow color is observed in the Sample solution, concomitantly determine the absorbances of the Sample solution and the Standard solution.

Acceptance criteria: The absorbance of the Sample solution does not exceed that of the Standard solution.

Bacterial Endotoxins Test 〈85〉: It contains NMT 0.6 USP Endotoxin Units/mg of procaine hydrochloride.

pH 〈791〉: 3.0–5.5

Other Requirements: Meets the requirements in Injections and Implanted Drug Products 〈1〉.

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in single-dose or in multiple-dose, light-resistant containers, preferably of Type I or Type II 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.

USP Reference Standards 〈11〉

USP Epinephrine Bitartrate RS

USP Procaine Hydrochloride RS