Spectrophotometric Determination of Chlorpheniramine in Some Dosage Forms Using the Charge – Transfer Complexation Technique

SUMMARY

A spectrophotometric method of assay of chlorpheniramine in some of its dosage forms based on the principle of charge transfer complexation between chlorpheniramine (the n – donor) and chloranilic acid (the π - acceptor) is described.

A 1:1 molecular complex with maximum absorption at 530 nm was formed. The association constant, molar absorptivity, and free energy change of the complex indicate that the complex has high stability. Beer's law was obeyed within the concentration range of 2 to 24 mg% (0.2 to 0.24 mg/ml.). The sensitivity of this method is 4.02 x 10⁻⁵M of chlorpheniramine base. There were high percentage recoveries when the method was employed to the quantitative determination of chlorpheniramine from commercial tablets and injection. This newly proposed method is easy, fast and requires minimum chemicals and equipment, and, therefore, could be utilized in the assay of chlorpheniramine in dosage forms.

Keywords::

• Charge transfer complex
• chloranilic acid
• chlorpheniramine
• association constant
• molar absorptivity
• spectrophotometric assay method.