Methamphetamine Hydrochloride

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

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

DOWNLOAD PDF HERE

1 DEFINITION

Methamphetamine Hydrochloride contains NLT 98.5% and NMT 100.5% of methamphetamine hydrochloride (C₁₀H₁₅N · HCl), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K (CN 1-May-2020)

B. Identification Tests—General, Chloride〈191〉

3 ASSAY

Procedure

Mobile phase: Prepare a degassed solution of 1.1 g of sodium 1-heptanesulfonate in a mixture of water, methanol, and diluted glacial acetic acid (7 in 50) (575:400:25). Adjust with acetic acid to a pH of 3.3 ± 0.1, if necessary. Filter through a 0.5-μm disk.

Standard solution: 0.2 mg/mL of USP Methamphetamine Hydrochloride RS in 0.12 M phosphoric acid. Sonicate if necessary.

Sample solution: 0.2 mg/mL of Methamphetamine Hydrochloride in 0.12 M phosphoric acid

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 257 nm

Column: 3.9-mm × 30.0-cm; packing L1

Flow rate: 2 mL/min

Injection volume: 20 μL

System suitability

Sample: Standard solution

Suitability requirements

Column e

ciency: NLT 1000 theoretical plates

Tailing factor: NMT 1.5

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of methamphetamine hydrochloride (C₁₀H₁₅N · HCl) in the portion of Methamphetamine 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 Methamphetamine Hydrochloride RS in the Standard solution (mg/mL)

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

Acceptance criteria: 98.5%–100.5% on the dried basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.1%

Ordinary Impurities 〈466〉

Standard solution and Sample solution: Chloroform

Eluant: Chloroform, cyclohexane, and diethylamine (5:4:1)

Visualization: 1

Acceptance criteria: Meets the requirements

5 SPECIFIC TESTS

Melting Range or Temperature 〈741〉: 171°–175°

Optical Rotation, Specific Rotation 〈781S〉

Sample solution: 20 mg/mL in water

Acceptance criteria: Between +16° and +19°

Loss on Drying 〈731〉

Analysis: Dry at 105° for 2 h.

Acceptance criteria: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

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

USP Reference Standards 〈11〉

USP Methamphetamine Hydrochloride RS