Dopamine 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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C₈H₁₁NO₂ · HCl             189.64

1,2-Benzenediol, 4-(2-aminoethyl)-, hydrochloride;

4-(2-Aminoethyl)pyrocatechol hydrochloride CAS RN: 62-31-7; UNII: 7L3E358N9L

1 DEFINITION

Dopamine Hydrochloride contains NLT 98.0% and NMT 102.0% of dopamine hydrochloride (C₈H₁₁NO₂ · HCl), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197A or _{(USP 1-Aug-2022)} 197K

Delete the following:

B. SPECTROSCOPIC IDENTIFICATION TESTS (197), Ultraviolet-Visible Spectroscopy: 1970

Sample solution: 40 µg/mL in Medium

Medium: Sodium bisulfite in water (1 in 1000) (USP 1-Aug-2022)

Add the following:

B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay _{(USP 1-Aug-2022)}

C. IDENTIFICATION TESTS-GENERAL (191), Chemical Identification Tests, Chloride: Meets the requirements

3 ASSAY

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PROCEDURE

Buffer: Dissolve 21 g of citric acid in 200 mL of 1 N sodium hydroxide in a 1-L flask. Dilute with water to volume. To 600 mL of this solution add 400 mL of 0.1 N hydrochloric acid.

Solution A: Dissolve 1.08 g of 1-octanesulfonic acid sodium salt in 880 mL of Buffer in a 1-L flask. Add 50 mL of methanol and 70 mL of acetonitrile.

Solution B: Dissolve 1.08 g of 1-octanesulfonic acid sodium salt in 700 mL of Buffer in a 1-L flask. Add 100 mL of methanol and 200 mL of acetonitrile.

Mobile phase: See Table 1.

Table 1

Standard solution: 0.5 mg/mL of USP Dopamine Hydrochloride RS in Solution A

Sample solution: 0.5 mg/mL of Dopamine Hydrochloride in Solution A

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 280 nm

Column: 3.9-mm x 15-cm; 4.0-µm packing 11

Flow rate: 1 mL/min

Injection volume: 10 µL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.5

Relative standard deviation: NMT 0.73%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of dopamine hydrochloride (C₈H₁₁NO₂ · HCl) in the portion of Dopamine Hydrochloride taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of dopamine from the Sample solution

r_s = peak response of dopamine from the Standard solution

C_s = concentration of USP Dopamine Hydrochloride RS in the Standard solution (mg/mL)

C_u = concentration of Dopamine Hydrochloride in the Sample solution (mg/mL) _{(USP 1-Aug-2022)}

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

4 IMPURITIES

RESIDUE ON IGNITION (281): NMT 0.1%

CHLORIDE AND SULFATE (221), Sulfate

Standard solution: 0.10 mL of 0.020 N sulfuric acid

Sample solution: 500 mg of Dopamine Hydrochloride in 40 mL of water

Acceptance criteria: Any turbidity produced in the Sample solution is NMT that produced in the Standard solution.

Change to read:

ORGANIC IMPURITIES

Buffer, Solution A, Solution B, Mobile phase, and Chromatographic system: Proceed as directed in the Assay.

System suitability solution: 0.024 mg/mL each of USP Dopamine Related Compound A RS and USP Dopamine Related Compound B.RS in Solution A

Sensitivity solution: 0.001 mg/mL of USP Dopamine Hydrochloride RS in Solution A

Standard solution: 0.002 mg/mL each of USP Dopamine Hydrochloride RS. USP Dopamine Related Compound A RS, USP Dopamine Related Compound B RS, and USP Dopamine Related Compound C RS in Solution A

Sample solution: 2.0 mg/mL of Dopamine Hydrochloride in Solution A

System suitability

Samples: System suitability solution, Sensitivity solution, and Standard solution

[NOTE-See Table 2 for the relative retention times.]

Suitability requirements

Resolution: NLT 5.0 between dopamine related compound B and dopamine related compound A, System suitability solution

Relative standard deviation: NMT 5.0% for dopamine related compound A, dopamine related compound B, and dopamine related compound C, Standard solution

Signal-to-noise ratio: NLT 20, Sensitivity solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of dopamine related compound A, dopamine related compound B, and dopamine related compound C in the portion of Dopamine Hydrochloride taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of dopamine related compound A, dopamine related compound B, or dopamine related compound C from the Sample solution

r_s = peak response of dopamine related compound A, dopamine related compound B, or dopamine related compound C from the Standard solution

C_s = concentration of the USP Dopamine Related Compound A RS, USP Dopamine Related Compound B RS, or USP Dopamine Related Compound C RS in the Standard solution (mg/mL)

C_u = concentration of Dopamine Hydrochloride in the Sample solution (mg/mL)

Calculate the percentage of any unspecied impurity in the portion of Dopamine Hydrochloride taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of any unspecied impurity from the Sample solution

r_s = peak response of dopamine hydrochloride from the Standard solution

C_s = concentration of USP Dopamine Hydrochloride RS in the Standard solution (mg/mL)

C_u = concentration of Dopamine Hydrochloride in the Sample solution (mg/mL)

Acceptance criteria: See Table 2. The reporting threshold is 0.05%.

Table 2

5 SPECIFIC TESTS

Delete the following:

READILY CARBONIZABLE SUBSTANCES TEST (271)

Sample solution: 100 mg of Dopamine Hydrochloride in 5 mL of sulfuric acid

Acceptance criteria: The solution has no more color than Matching Fluid A (see Color and Achromicity (631), Color Determination and Standards) _{(USP 1-Aug-2022)}

PH (791)

Sample solution: 1 in 25

Acceptance criteria: 3.0-5.5

LOSS ON DRYING (731)

Analysis: Dry at 105° for 2 h.

Acceptance criteria: NMT 0.5%

Delete the following:

CLARITY AND COLOR OF SOLUTION

Sample solution: 400 mg of Dopamine Hydrochloride in 10 ml of sodium bisulfite solution (1 in 1000)

Acceptance criteria: This solution is clear and colorless, or practically colorless. (USP 1-Aug-2022)

6 ADDITIONAL REQUIREMENTS

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PACKAGING AND STORAGE: Preserve in tight containers. Store at controlled (USP 1-Aug-2022) room temperature.

Change to read:

USP REFERENCE STANDARDS (11)

USP Dopamine Hydrochloride RS

USP Dogamine Related Compound A RS

5-(2-Aminoethyl)-2-methoxyphenol.

C₉H₁₃NO₂         167.21

USP Dopamine Related Compound B RS

4-(2-Aminoethyl)-2-methoxyphenol.

C₉H₁₃NO₂        167.21

USP Dopamine Related Compound C RS

2-(3,4-Dimethoxyphenyl)ethan-1-amine.

C₁₀H₁₅NO₂             181.23 _{(USP 1-Aug-2022)}