Hyoscyamine Sulfate Elixir

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

Hyoscyamine Sulfate Elixir contains NLT 90.0% and NMT 110.0% of the labeled amount of hyoscyamine sulfate

[(C₁₇H₂₃NO₃)₂ · H₂SO₄ · 2H₂O].

2 IDENTIFICATION

A. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

Procedure

Buffer:

Transfer 13.6 g of monobasic potassium phosphate to a 2000-mL volumetric flask, and dissolve in about 1800 mL of water. Adjust with phosphoric acid to a pH of 3.0 ± 0.1, dilute with water to volume, and filter.

Mobile phase:

Methanol and Buffer (25:75), degassed

Diluent:

0.01 N hydrochloric acid

Standard stock solution:

0.16 mg/mL of anhydrous hyoscyamine sulfate from USP Hyoscyamine Sulfate RS in Diluent.

[Note—This solution may be stored in a refrigerator for 30 days.]

Standard solution:

4.8 µg/mL of anhydrous hyoscyamine sulfate from the Standard stock solution in Diluent

Tropic acid solution:

4 µg/mL of tropic acid in Diluent

System suitability solution:

Transfer 3.0 mL of the Standard stock solution into a 100-mL volumetric flask, add 4.0 mL of the Tropic acid solution, and dilute with Diluent to volume.

Sample solution:

5 µg/mL of hyoscyamine sulfate from an appropriate volume of Elixir in Diluent. Pass an aliquot through a suitable filter of 0.45-µm pore size, and discard the first 5 mL of the filtrate.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 205 nm

Columns

Guard: 3-mm × 4-mm; packing L11

Analytical: 4.6-mm × 15-cm; 4-µm packing L11

Column temperature: 30°

Flow rate: 1.0 mL/min

Injection volume: 50 µL

System suitability

Sample: System suitability solution

[Note—The elution order is the tropic acid peak, followed by the hyoscyamine peak.]

Suitability requirements

Resolution: NLT 1.5 between tropic acid and hyoscyamine

Tailing factor: NMT 2.0 for the hyoscyamine peak

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of hyoscyamine sulfate

[(C₁₇H₂₃NO₃)₂ · H₂SO₄ · 2H₂O] in the portion of Elixir taken:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × (Mᵤ / Mₛ) × 100

rᵤ = peak response from the Sample solution

rₛ = peak response from the Standard solution

Cₛ = concentration of anhydrous hyoscyamine sulfate in the Standard solution (µg/mL)

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

Mᵤ = molecular weight of hyoscyamine sulfate, 712.85

Mₛ = molecular weight of anhydrous hyoscyamine sulfate, 676.83

Acceptance criteria: 90.0%–110.0%

4 SPECIFIC TESTS

pH 〈791〉: 3.0–6.5

Alcohol Determination 〈611〉:

90.0%–110.0% of the labeled amount of alcohol (C₂H₅OH)

5 ADDITIONAL REQUIREMENTS

Packaging and Storage:

Preserve in tight, light-resistant containers, and store at controlled room temperature.

USP Reference Standards 〈11〉

USP Hyoscyamine Sulfate RS