Dyphylline and Guaifenesin Oral Solution

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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1 DEFINITION

Dyphylline and Guaifenesin Oral Solution contains NLT 90.0% and NMT 110.0% of the labeled amounts of dyphylline (C₁₀H₁₄N₄O₄) and guaifenesin (C₁₀H₁₄O₄)

2 IDENTIFICATION

A. The UV spectra of the major peaks of the Sample solution correspond to those of the Standard solution, as obtained in the Assay.

B. The retention times of the major peaks of the Sample solution correspond to those of the Standard solution, as obtained in the Assay.

3 ASSAY

PROCEDURE

Buffer: 0.01 M monobasic potassium phosphate

Mobile phase: Methanol and Buffer (21:79)

System suitability solution: 0.1 mg/ml. each of USP Guaifenesin RS and USP Dypbylline RS and 0.01 mg/ml. of guaiacol in Mobile phase

Standard solution: 0.1 mg/ml, of USP Guaifenesin RS and 0.1J mg/mt. of USP Dyphylline RS in Mobile phase, J being the ratio of the labeled

amount of dyphylline to that of guaifenesin

Sample solution: Nominally 0.1 mg/ml of guaifenesin, prepared as follows. Transfer 100 mg of guaifenesin from a volume of Oral Solution to a 100-mL volumetric flask, and dilute with Mobile phase to volume. Transfer 5.0 mL of this solution to a 50-mL volumetric flask, and dilute with Mobile phase to volume.

Chromatographic system

(See Chromatography (621), System Suitability)

Mode: LC

Detector: UV 230 nm. For identification test A, use a diode array detector in the range of 200-400 nm.

Columns

Guard: Packing LT

FFIC

Analytical: 4.6-mm 15-cm; packing L1

Flow rate: 2 mL/min

Injection volume: 20 µL

System suitability

Samples: System suitability solution and Standard solution

[NOTE-The relative retention times for dyphylline, guaiacol, and guaifenesin are about 0.25, 0.7, and 1.0, respectively.)

Suitability requirements

Resolution: NLT 1.8 between the guaiacol and guaifenesin peaks, NLT 9.0 between the guaiacol and dyphylline peaks, Systern suitability solution

Relative standard deviation: NMT 2.0% for both dyphylline and guaifenesin, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentages of the labeled amounts of dyphylline (CH, NO) and guaifenesin (C,H,O) in the portion of Oral Solution taken

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

r_U = peak response of dyphylline or guaifenesin from the Sample solution

r_S = peak response of dyphylline or guaifenesin from the Standard solution

C_S = concentration of USP Dyphylline RS or USP Guaifenesin RS in the Standard solution (mg/mL)

C_U = Cnominal concentration of dyphylline or guaifenesin in the Sample solution (mg/ml.)

Acceptance criteria: 90.0%-110.0% of the labeled amount of dyphylline (C₁₀H₁₄N₄O₄) and 90.0%-110.0% of the labeled amount of guaifenesin (C₁₀H₁₄O₄)

4 OTHER COMPONENTS

ALCOHOL DETERMINATION Method Ifb (611); 90.0%-110.0% of the labeled amount of alcohol (CHOH)

5 SPECIFIC TESTS

pH(791): 5.0-7.0

6 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers.