Hydrazones of isoniazid for colorimetric analysis

Area of Science:

• Analytical Chemistry
• Organic Chemistry
• Pharmaceutical Analysis

Background:

• Isoniazid is a critical first-line antituberculosis drug.
• Accurate quantification of isoniazid is essential for therapeutic drug monitoring and quality control.
• Existing analytical methods may have limitations in sensitivity or specificity.

Purpose of the Study:

• To develop and validate two novel, sensitive colorimetric methods for isoniazid determination.
• To investigate the reaction mechanisms involving Schiff base formation.
• To establish the linearity and reliability of the proposed analytical methods.

Main Methods:

• Colorimetric analysis of isoniazid using 4-nitrobenzaldehyde as a chromogenic reagent.
• Colorimetric analysis of isoniazid using pyridoxal as a chromogenic reagent.
• Spectrophotometric measurement of absorbance and construction of calibration curves.

Main Results:

• Both 4-nitrobenzaldehyde and pyridoxal yielded sensitive color reactions with isoniazid.
• The reactions proceed via the formation of hydrazone Schiff bases.
• Linear relationships between absorbance and isoniazid concentration were observed for both methods.

Conclusions:

• The developed colorimetric methods offer sensitive and reliable approaches for isoniazid quantification.
• These methods are suitable for routine analysis in pharmaceutical and clinical settings.
• The Schiff base formation provides a robust basis for isoniazid detection.