Dipyridamole Compounded Oral Suspension

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

Dipyridamole Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of dipyridamole (C₂₄H₄₀N₈O₄).

Prepare Dipyridamole Compounded Oral Suspension 10 mg/mL as follows (see Pharmaceutical Compounding-Nonsterile Preparations (795)).

Place the required number of tablets into a suitable mortar and comminute to a fine powder, or add Dipyridamole powder to the mortar. Add 20 mL of Vehicle, and mix to a uniform paste. Add Vehicle in small portions, and mix well after each addition. Transfer, stepwise and quantitatively, to a graduated or calibrated bottle. Add Vehicle in portions to rinse the mortar, add sufficient Vehicle to bring to final volume, and mix well.

2 ASSAY

2.1 PROCEDURE

Solution A: 1 mg/mL of dibasic sodium phosphate. Adjust with dilute phosphoric acid (1 in 3) to a pH of 4.6.

Mobile phase: Methanol and Solution A (75:25). Pass through a membrane filter of a 0.5-um pore size, and degas.

Standard solution: 100 µg/mL of USP Dipyridamole RS in Mobile phase

Sample solution: Agitate the container of Oral Suspension for 30 min on a rotating mixer, remove a 5-mL sample, and store in a clear glass vial at-70° until analyzed. At the time of analysis, remove the sample from the freezer, allow it to reach room temperature, and mix on a vortex mixer for 30 s. Pipet 1.0 mL of the sample into a 100-mL volumetric flask, and dilute with Mobile phase to volume.

2.1.1 Chromatographic system

(See Chromatography (621), System Suitability)

Mode: LC

Detector: UV 288 nm

Column: 4.6-mm x 25-cm; 5-µm packing L1

Flow rate: 1.3 mL/min

Injection volume: 20 µL

2.1.2 System suitability

Sample: Standard solution

[NOTE-The retention time for dipyridamole is about 7.3 min.]

2.1.3 Suitability requirements

Relative standard deviation: NMT 2.3% for replicate injections

2.1.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of dipyridamole (C₂₄H₄₀N₈O₄) in the portion of Oral Suspension taken:

                Result = (r_U/r_S) x (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 Dipyridamole RS in the Standard solution (µg/mL)

C_U = nominal concentration of dipyridamole in the Sample solution (µg/mL)

Acceptance criteria: 90.0%-110.0%

3 SPECIFIC TESTS

PH (791): 3.8-4.8

4 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Package in tight, light-resistant containers. Store at controlled room temperature, or in a refrigerator.

BEYOND-USE DATE: NMT 60 days after the date on which it was compounded when stored at controlled room temperature, or in a refrigerator

LABELING: Label it to state that it is to be well shaken, and to state the Beyond-Use Date.

USP REFERENCE STANDARDS (11)

USP Dipyridamole RS