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Developing Metal Complexes for Captopril Quantification in Tablets Using Potentiometric and Conductometric Methods
Badriah Saad Al-Farhan1, Anas Alfarsi2, Laila H Abdel-Rahman3
1Chemistry Department, Faculty of Girls for Science, King Khalid University, Abha 61421, Saudi Arabia.
ACS Omega
|January 23, 2023
Summary
Potentiometric and conductometric methods were used to study captopril (CAP) interactions with 10 metal ions. These techniques successfully determined CAP in pure powder and tablet forms, showing high recovery rates without interference.
Area of Science:
- Analytical Chemistry
- Coordination Chemistry
- Pharmaceutical Analysis
Background:
- Captopril (CAP) is a widely used antihypertensive drug.
- Accurate determination of CAP in pharmaceutical formulations is crucial for quality control.
- Understanding metal-ion interactions with CAP can inform its chemical behavior and analytical applications.
Purpose of the Study:
- To investigate the interaction between captopril (CAP) and ten different metal ions using potentiometric and conductometric methods.
- To evaluate the ionization and stability constants of the CAP-metal complexes.
- To develop and validate analytical methods for determining CAP in pure and tablet forms.
Main Methods:
- Potentiometric and conductometric titrations were employed to study the complexation of CAP with Cr3+, Fe3+, La2+, Th4+, Co2+, Mn2+, Pd2+, Sr2+, Ti2+, and Zr2+.
- The ionization constant of CAP and stability constants (log K) of the metal-CAP complexes were calculated.
- The standard addition method (SAM) based on the Gran plot was used for quantitative determination of CAP.
Main Results:
- Complexes with metal:ligand ratios of 1:1, 1:2, and/or 1:3 were formed.
- Both potentiometric and conductometric methods confirmed the stoichiometry of the binary complexes.
- CAP was accurately determined in the concentration range of 0.83-13.04 mg/mL with a detection limit of 0.64 mg/mL.
- Recovery percentages from tablet formulations ranged from 95.88% to 99.92% with no observed interference from common excipients.
Conclusions:
- Potentiometric and conductometric methods are effective for studying metal-CAP interactions and determining CAP in pharmaceutical samples.
- The developed analytical procedures are reliable, accurate, and suitable for routine quality control of CAP in powder and tablet forms.
- The study provides valuable insights into the coordination chemistry of captopril with various metal ions.
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