Abstract

Spectrophotometric determination of alendronate in pharmaceutical formulations via complex formation with Fe (II) ions

Author(s): Jamil Rima, Chawki Boukarim, Mohamad Mroueh, Soula Kyrakoss, Karine Assaker

The formation of a complex between alendronate sodium, a non-chromophoric bisphosphonate, and iron (II) chloride in aqueous solution at pH = 6 was studied. The stoichiometric ratio of alendronate to Fe (II) ions was determined. Linear and non linear regression methods were used to estimate the complexation constant (K).A1:1 stoichiometric ratio was observed for the binary complex between Fe (II) and alendronate with a formation constant of 770 ± 10 M-1.L. Subsequently, a spectrophotometric method was developed for the determination of alendronate in the concentration range 3.25-325g/mL, the recovery valuewas 97%± 3 and the limit of detection was 1g/mL. The method was validated for the direct determination of alendronate in tablet dosage formulation.