Chemiluminometric determination of captopril in a multi-pumping flow system

Area of Science:

• Analytical Chemistry
• Pharmaceutical Analysis
• Chemiluminescence

Background:

• Captopril is a widely used angiotensin II-converting-enzyme (ACE) inhibitor.
• Accurate determination of captopril in pharmaceutical formulations is crucial for quality control.
• Existing analytical methods may lack automation, speed, or cost-efficiency.

Purpose of the Study:

• To develop a simple, versatile, and fully automated analytical methodology for chemiluminometric determination of captopril.
• To utilize the captopril-enhanced chemiluminescence of tris(2,2'-bipyridyl)ruthenium(II) for quantification.
• To validate the method for pharmaceutical formulations.

Main Methods:

• A fully automated analytical methodology employing a multi-pumping flow system (MPFS).
• Utilized the chemiluminescence enhancement of tris(2,2'-bipyridyl)ruthenium(II) by captopril in a sulphuric acid medium.
• Employed three solenoid micro-pumps for precise control of solution flow and mixing.

Main Results:

• The method allowed captopril determination in the concentration range of 2×10⁻³ to 1.5×10⁻¹ mmolL⁻¹ with high linearity (r=0.9996).
• Achieved a sampling frequency of approximately 58 determinations per hour with minimal waste (620 μL per determination).
• Results for pharmaceutical formulations were statistically comparable to the reference procedure, with relative deviations between -2.32% and 1.39%.

Conclusions:

• The proposed automated chemiluminometric method is simple, versatile, efficient, and cost-effective for captopril determination.
• The methodology provides accurate and reproducible results for pharmaceutical formulations.
• The system's automation and low-cost components make it suitable for routine quality control analysis.