Pilocarpine 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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C₁₁H₁₆N₂O₂ · HCl 244.72

2(3H)-Furanone, 3-ethyldihydro-4-[(1-methyl-1H-imidazol-5-yl)methyl]-, monohydrochloride, (3S-cis)-; Pilocarpine monohydrochloride CAS RN®: 54-71-7; UNII: 0WW6D218XJ.

1 DEFINITION

Pilocarpine Hydrochloride contains NLT 98.0% and NMT 102.0% of C₁₁H₁₆N₂O₂· HCl, calculated on the dried basis. 

2 IDENTIFICATION

Change to read:

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

B. Identification Tests—General, Chloride〈191〉: Meets the requirements

Sample solution: 50 mg/mL

3 ASSAY

Procedure

Buffer: 4.4 g/L of dibasic potassium phosphate in water. Adjust with phosphoric acid to a pH of 6.5 ± 0.1.

Mobile phase: Acetonitrile, methanol, and Buffer (2:35:63)

Standard solution: 0.5 mg/mL of USP Pilocarpine Hydrochloride RS in water. [Note—Sonicate if necessary.] System suitability solution: Transfer a known quantity of USP Pilocarpine Hydrochloride RS in a suitable volumetric flask, and add water, equivalent to 10% of the volume of the flask, to dissolve. [Note—Sonicate as needed.] Add 0.1 N sodium hydroxide, equivalent to 10% of the volume of the flask, quench immediately with the same volume of 0.1 N hydrochloric acid, and mix. Dilute with water to volume. [Note—The initial concentration of USP Pilocarpine Hydrochloride RS is 0.5 mg/mL. Isopilocarpine is formed in the System suitability solution preparation.]

Sample solution: 0.5 mg/mL of Pilocarpine Hydrochloride in water. [Note—Sonicate if necessary.]

3.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 215 nm

Column: 4.6-mm × 15-cm; 3-µm packing L11

Column temperature: 35°

Flow rate: 1.0 mL/min

Injection size: 10 µL

3.2 System suitability

Samples: Standard solution and System suitability solution

Suitability requirements

Resolution: NLT 1.5 between isopilocarpine and pilocarpine, System suitability solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 2.0%, Standard solution

3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of C₁₁H₁₆N₂O₂ · HCl in the portion of Pilocarpine Hydrochloride taken:

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

r_U = peak area from the Sample solution

r_S = peak area from the Standard solution

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

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

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

4 IMPURITIES

Organic Impurities

4.1 Procedure 1: Related Compounds

Mobile phase, Standard solution, System suitability solution, and Sample solution: Proceed as directed in the Assay. Sensitivity solution: 0.25 µg/mL of USP Pilocarpine Hydrochloride RS in water from the Standard solution

4.1.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 215 nm

Column: 4.6-mm × 15-cm; 3-µm packing L11

Column temperature: 35°

Flow rate: 1.0 mL/min

Run time: NLT 5 times the retention time of the pilocarpine peak

Injection size: 10 µL

4.1.2 System suitability

Suitability requirements

Resolution: NLT 1.5 between isopilocarpine and pilocarpine, System suitability solution

Signal-to-noise ratio: NLT 10 for the pilocarpine peak, Sensitivity solution

Relative standard deviation: NMT 2.0% for the pilocarpine peak, Standard solution

4.1.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Pilocarpine Hydrochloride taken:

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

r_U = peak area of each individual impurity from the Sample solution

r_S = peak area of pilocarpine from the Standard solution

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

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

4.1.4 Acceptance criteria

Individual impurities: See Impurity Table 1. [Note—Disregard any unspecified impurity peaks less than 0.05%.]

Total impurities: NMT 1.0%

Impurity Table 1

a (3R,4R)-3-Ethyl-4-[(1-methyl-1H-imidazol-5-yl)methyl]dihydrofuran-2(3H)-one.

b (2S,3R)-2-Ethyl-4-hydroxy-3-[(1-methyl-1H-imidazol-5-yl)methyl]butanoic acid.

c (2R,3R)-2-Ethyl-4-hydroxy-3-[(1-methyl-1H-imidazol-5-yl)methyl]butanoic acid.

4.2 Procedure 2: Other Alkaloids

Sample solution: 10 mg/mL in water

Analysis: Divide the Sample solution into two portions. To one portion add a few drops of 6 N ammonium hydroxide, and to the other, add a few drops of potassium dichromate TS.

Acceptance criteria: No turbidity is produced in either solution.

5 SPECIFIC TESTS

Optical Rotation, Specific Rotation〈781S〉: +88.5° to +91.5°

Sample solution: 20 mg/mL, in water

Loss on Drying 〈731〉: Dry a sample at 105° for 2 h: it loses NMT 3.0% of its weight.

Readily Carbonizable Substances Test 〈271〉

Sample solution: 50 mg/mL in sulfuric acid

Acceptance criteria: The solution has no more color than Matching Fluid B.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers. Store at room temperature.

USP Reference Standards 〈11〉

USP Pilocarpine Hydrochloride RS