Captopril Oral Solution
DEFINITION
Captopril Oral Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of captopril (C9H15NO3S).
Prepare Captopril Oral Solution 0.75 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 
795
).
795).| Captopril powder | 75 mg |
| Vehicle for Oral Solution (regular or sugar-free), NF, a sufficient quantity to make | 100 mL |
Add Captopril 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 final volume, and mix well.
ASSAY
• Procedure
Mobile phase:
Methanol and water (55:45) containing 0.5 mL/L of phosphoric acid. Filter, and degas.
Standard solution:
7.5 µg/mL of USP Captopril RS
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 sample into a 100-mL volumetric flask, and dilute with Mobile phase to volume.
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 sample into a 100-mL volumetric flask, and dilute with Mobile phase to volume.
Chromatographic system
Mode:
LC
Detector:
UV 220 nm
Column:
4.6-mm × 25-cm; 5-µm packing L1
Flow rate:
1 mL/min
Injection volume:
20 µL
System suitability
Sample:
Standard solution
[Note—The retention time for captopril is about 5.0 min. ]
Suitability requirements
Relative standard deviation:
NMT 0.9% for replicate injections
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of the labeled amount of captopril (C9H15NO3S) in the portion of Oral Solution taken:
Result = (rU/rS) × (CS/CU) × 100
| rU | = | = peak response from the Sample solution |
| rS | = | = peak response from the Standard solution |
| CS | = | = concentration of captopril in the Standard solution (µg/mL) |
| CU | = | = nominal concentration of captopril in the Sample solution (µg/mL) |
Acceptance criteria:
90.0%–110.0%
SPECIFIC TESTS
• pH 791:
3.8–4.3
791:
3.8–4.3
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Package in tight, light-resistant containers. Store in a cold place.
• Labeling:
Label it to state the Beyond-Use Date.
• Beyond-Use Date:
NMT 7 days after the date on which it was compounded
• USP Reference Standards 11
11
USP Captopril RS 
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Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Jeanne H. Sun, Pharm.D.
Associate Scientific Liaison (301) 230-3361 |
(CMP2010) Compounding |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP38–NF33 Page 2577
Pharmacopeial Forum: Volume No. 40(5)