Diltiazem Hydrochloride Compounded 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 

Diltiazem Hydrochloride Compounded Oral Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of diltiazem hydrochloride (C₂₂H₂₆N₂O₄S. HCl). 

Prepare Diltiazem Hydrochloride Compounded Oral Solution 12 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉). 

Add Diltiazem Hydrochloride powder and 10 mL of Vehicle to a mortar, and mix. Add the Vehicle in small portions almost to volume, and mix thoroughly after each addition. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add enough Vehicle to bring to nal volume, and mix well. 

2 ASSAY 

2.1 Procedure 

Solution A: 1.16 mg/mL of d-10-camphorsulfonic acid in 0.1 M sodium acetate. Adjust with 0.1 N sodium hydroxide to a pH of 6.2. Mobile phase: Acetonitrile, methanol, and Solution A (50:25:25) 

Standard solution: 120 µg/mL of USP Diltiazem Hydrochloride RS in Mobile phase 

Sample solution: Agitate the container of Oral Solution 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 with a vortex mixer for 30 s. Pipet 1.0 mL of the solution to a 100-mL volumetric ask, and dilute with Mobile phase to volume. 

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: 1.5 mL/min 

Injection volume: 20 µL 

System suitability 

Sample: Standard solution 

[Note—The retention time for diltiazem is about 9.6 min.] 

Suitability requirements 

Relative standard deviation: NMT 1.3% for replicate injections 

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of the labeled amount of diltiazem hydrochloride (C₂₂H₂₆N₂O₄S. HCl) in the portion of Oral Solution taken: 

Result = (r_u/r_s) × (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 Diltiazem Hydrochloride RS in the Standard solution (µg/mL)  

C_u = nominal concentration of diltiazem hydrochloride in the Sample solution (µg/mL) 

Acceptance criteria: 90.0%–110.0% 

SPECIFIC TESTS 

2.2 pH 〈791〉: 3.7–4.7 

3 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 the Beyond-Use Date. 

USP Reference Standards 〈11〉 

USP Diltiazem Hydrochloride RS