Thermodynamic study of complex formation of β-cyclodextrin with ibuprofen by conductometric method and determination of ibuprofen in pharmaceutical drugs

The equilibrium constants and the thermodynamic parameters for complex formation of β-cyclodextrin (β-CD) with ibuprofen have been determined by conductivity measurements in water. The inclusion complexation of ibuprofen in β-cyclodextrin (β-CD) has been examined by means of the conductometric method. The results suggest that stable1:1 complex is formed between ibuprofen and β-cyclodextrin. The thermodynamic parameters (ΔHc°,ΔSc°) for this complexation reaction have been determined from temperature dependence of the stability constant using the van’t Hoff plots. Based on the obtained results, a conductometric method for the determination of ibuprofen in the presence of β-CD at 25 °C was developed in the range of 10−3–10−5 mol dm−1. The method was satisfactorily applied to the quantification of ibuprofen in pharmaceutical preparations.