Spectrophotometric study of diclofenac-Fe(III) complex

Area of Science:

• Analytical Chemistry
• Spectrophotometry
• Coordination Chemistry

Background:

• Diclofenac sodium is a widely used non-steroidal anti-inflammatory drug.
• Accurate and sensitive analytical methods are crucial for its quantification.
• Existing methods may have limitations in sensitivity or complexity.

Purpose of the Study:

• To develop and optimize a novel spectrophotometric method for diclofenac sodium determination.
• To investigate the complexation reaction between diclofenac sodium and Fe(III) ions.
• To establish the optimal conditions for complex formation, extraction, and spectrophotometric measurement.

Main Methods:

• Multifactor optimization technique including factorial design and response surface methodology.
• Spectrophotometric analysis of the formed diclofenac-Fe(III) complex.
• Study of variables such as pH, ionic strength, and reagent concentration.
• Determination of conditional stability constant using Sommer and Job methods.

Main Results:

• A new spectrophotometric method for diclofenac sodium analysis was successfully developed.
• Diclofenac sodium forms a red, chloroform-extractable (2:1) complex with Fe(III) chloride in the presence of ammonium thiocyanate.
• Optimal reaction conditions were determined: pH 4.2-6.5, maximum absorbance at 481 nm.
• The conditional stability constant was found to be 10(6.4) at pH 6.0 and ionic strength 0.19M.
• The method demonstrated good linearity with Beer's law up to 1 mmol L(-1), with 98.8% recovery and a lower limit of sensitivity of 14.7 µg mL(-1).

Conclusions:

• The developed multifactor optimized spectrophotometric method is effective for the accurate determination of diclofenac sodium.
• The method is sensitive, reliable, and suitable for routine analysis.
• The complexation reaction and optimal conditions provide a robust basis for quantitative analysis.