Amiloride 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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C₆H₈ClN₇O · HCl · 2H₂O 302.12

Pyrazinecarboxamide, 3,5-diamino-N-(aminoiminomethyl)-6-chloro-, monohydrochloride dihydrate;

N-Amidino-3,5-diamino-6-chloropyrazinecarboxamide monohydrochloride dihydrate;

3,5-Diamino-N-carbamimidoyl-6-chloropyrazine-2-carboxamide hydrochloride dihydrate (USP 1-Aug-2022) CAS RN®: 17440-83-4; UNII:FZJ37245UC.

Amiloride hydrochloride (anhydrous)

C₆H₈ClN₇O · HCl  266.09 CAS RN®: 2016-88-8; UNII: 7M458Q65S3.

Amiloride (free base)

C₆H₈ClN₇O 229.63 CAS RN®: 2609-46-3; UNII: 7DZO8EB0Z3. (USP 1-Aug-2022)

Change to read:

1 DEFINITION

Amiloride Hydrochloride contains NLT 98.0% and NMT 102.0% (USP 1-Aug-2022) of amiloride hydrochloride (C H ClN O · HCl), calculated on the anhydrous (USP 1-Aug-2022) basis.

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197M or 197A (USP 1-Aug-2022)

Change to read:

B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay. (USP1-Aug-2022)

C. Identification Tests-General 〈191〉, Chemical Identification Tests, Chloride: Meets the requirements

3 ASSAY

Change to read:

3.1 Procedure

Mobile phase: Dissolve 0.8 g of sodium 1-hexanesulfonate, monohydrate in 900 mL of water. Add 100 mL of acetonitrile. Adjust with phosphoric acid to a pH of 3.0.

Standard solution: 0.1 mg/mL of USP Amiloride Hydrochloride RS in Mobile phase

Sample solution: 0.1 mg/mL of Amiloride Hydrochloride in Mobile Phase

3.2 Chromatographic system

Mode: LC

Detector: UV 210 nm

Column: 4.0-mm × 12.5-cm; 5-μm packing L7

Flow rate: 1.5 mL/min

Injection volume: 10 μL

Run time: NLT 2 times the retention time of amiloride

3.3 System suitability

Sample: Standard solution

3.4 Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 0.73%

3.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of amiloride hydrochloride (C₆H₈ClN₇O · HCl) in the portion of Amiloride Hydrochloride taken:

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = peak response of amiloride from the Sample solution

r_s = peak response of amiloride from the Standard solution

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

C_u = concentration of Amiloride Hydrochloride in the Sample solution (mg/mL) (USP 1-Aug-2022)

Acceptance criteria: 98.0%–102.0% (USP 1-Aug-2022) on the anhydrous (USP 1-Aug-2022) basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.1%

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4.1 Organic Impurities

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

Standard solution: 1 μg/mL each of USP Amiloride Hydrochloride RS and USP Amiloride Related Compound A RS in Mobile phase

Sensitivity solution: 0.5 μg/mL each of USP Amiloride Hydrochloride RS and USP Amiloride Related Compound A RS in Mobile phase, from

4.2 Standard solution

Sample solution: 1 mg/mL of Amiloride Hydrochloride in Mobile phase

4.3 System suitability

Samples: Standard solution and Sensitivity solution

4.4 Suitability requirements

Relative standard deviation: NMT 5.0% for amiloride and amiloride related compound A, Standard solution

Signal-to-noise ratio: NLT 10 for amiloride and amiloride related compound A, Sensitivity solution

4.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of amiloride related compound A in the portion of Amiloride Hydrochloride taken:

Result = (r_u/r_s) × (C_s/C_u) × 100

r_u = peak response of amiloride related compound A from the Sample solution

r_s = peak response of amiloride related compound A from the Standard solution

C_s = concentration of USP Amiloride Related Compound A RS in the Standard solution (mg/mL)

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

Calculate the percentage of amiloride acid, 5-hydroxyamiloride, and any unspecified impurity in the portion of Amiloride Hydrochloride taken:

Result = (r_u/r_s) × (C_s/C_u) × (1/F) × 100

r_u = peak response of amiloride acid, 5-hydroxyamiloride, or any unspecified impurity from the Sample solution

r_s = peak response of amiloride from the Standard solution

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

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

F = relative response factor (see Table 1)

Acceptance criteria: See Table 1. The reporting threshold is 0.05%.

Table 1

^a 3,5-Diamino-6-chloropyrazine-2-carboxylic acid.

^b 3-Amino-N-carbamimidoyl-6-chloro-5-hydroxypyrazine-2-carboxamide.

5 SPECIFIC TESTS

Acidity

Sample: 1.0 g

Analysis: Dissolve the Sample in 100 mL of a mixture of methanol and water (1:1). Titrate with 0.10 N sodium hydroxide to a potentiometric endpoint.

Acceptance criteria: NMT 0.30 mL is required (0.1% as hydrochloride).

Delete the following:

Loss on Drying

(See Thermal Analysis 〈891〉.)

[Note-The quantity taken for the determination may be adjusted, if necessary, for instrument sensitivity.]

Sample: 10 mg

Analysis: Determine the percentage of volatile substances by thermogravimetric analysis on an appropriately calibrated instrument using the Sample. Heat the specimen at the rate of 10°/min between ambient temperature and 225° in an atmosphere of nitrogen at a flow rate of 40 mL/min. From the thermogram determine the accumulated loss in weight between ambient temperature and about 200° on the plateau.

Acceptance criteria: 11.0%–13.0% (USP 1-Aug-2022)

Add the following:

Water Determination 〈921〉, Method I, Method Ia

Sample: 0.2 g

Acceptance criteria: 11.0%–13.0% (USP 1-Aug-2022)

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

Change to read:

USP Reference Standards 〈11〉

USP Amiloride Hydrochloride RS

USP Amiloride Related Compound A RS

Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate.

C₆H₇ClN₄O₂   202.60 (USP 1-Aug-2022)