Polarographic determination of isosorbide dinitrate

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Pharmaceutical Analysis

Background:

• Isosorbide dinitrate is a vasodilator used to treat angina.
• Accurate quantification of organic nitrates is crucial for pharmaceutical quality control.
• Existing analytical methods may have limitations in sensitivity or cost.

Purpose of the Study:

• To develop and validate a polarographic method for the quantitative analysis of isosorbide dinitrate.
• To assess the method's applicability for content uniformity determination in pharmaceutical formulations.
• To compare the polarographic method with existing analytical techniques.

Main Methods:

• Polarographic reduction of isosorbide dinitrate and its mononitrate isomers in aqueous solutions.
• Measurement of current at -1.6 V versus saturated calomel electrode.
• Assay of pharmaceutical formulations using the developed polarographic method.

Main Results:

• The polarographic current was proportional to organic nitrate concentration (10-100 µg/ml).
• The method showed no interference from inorganic nitrate.
• Mononitrate isomers produced an additive response, preventing individual determination.
• Precision and accuracy were comparable to automated colorimetric analysis.
• The method was validated against IR and colorimetric analyses for commercial formulations.

Conclusions:

• Polarography provides a sensitive, specific, and precise method for analyzing isosorbide dinitrate.
• The technique is suitable for single-tablet assay and content uniformity testing.
• This method offers advantages in terms of sample preparation and apparatus cost.