Isradipine 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

Isradipine Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of isradipine (C₁₉H₂₁N₃O₅).

Prepare Isradipine Compounded Oral Suspension 1 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

a DynaCirc 5-mg capsules, Sandoz Pharmaceuticals, East Hanover, NJ.

b Isradipine powder, Sandoz, East Hanover, NJ.

Calculate the required quantity of each ingredient for the total amount to be prepared. If using Isradipine capsules, empty the required number in a suitable mortar, or use Isradipine powder. Add sufficient Glycerin to wet the powder, and triturate to a fine paste. Add the Syrup in small portions. Add increasing volumes of the Syrup to make an isradipine liquid that is pourable. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add enough of the Syrup to bring to final volume, and mix well.

2 ASSAY

Procedure

Mobile phase: Methanol, tetrahydrofuran, and water (42:20:38). Filter, and degas.

Diluent: Prepare a solution of methanol and 95% Ethanol (50:50).

Standard stock solution: 1.0 mg/mL of USP Isradipine RS in Diluent

Standard solution: Prepare 0.1 mg/mL of isradipine from Standard stock solution and Diluent, and pass through a filter of 0.22-μm pore size.

Sample solution: Shake thoroughly by hand each bottle of Oral Suspension. Prepare 0.1 mg/mL of isradipine from Oral Suspension and

Diluent, and pass through a filter of 0.22-μm pore size.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 240 nm

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

Flow rate: 1.0 mL/min

Injection volume: 10 μL

System suitability

Sample: Standard solution

[Note—The retention time for isradipine is about 6.1 min.]

Suitability requirements

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of isradipine (C₁₉H₂₁N₃O) 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 Isradipine RS in the Standard solution (mg/mL)

C_U = nominal concentration of isradipine in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

pH 〈791〉: 5.5–6.5

4 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in tight, light-resistant containers. Store in a refrigerator.

Beyond-Use Date: NMT 30 days after the date on which it was compounded, when stored in a refrigerator

Labeling: Label it to indicate that it is to be well shaken before use, and to state the Beyond-Use Date.

USP Reference Standards 〈11〉

USP Isradipine RS