Beta- and gamma-cyclodextrin ionophores as electroactive materials for construction of new polyvinyl chloride sensors for eletriptan based on host-guest recognition

The construction and development of polyvinyl chloride environmentally-friendly sensors for eletriptan hydrobromide (ELT) are developed. The sensing materials incorporated β- or γ-cyclodextrin as the electroactive material (sensor 1 and 2, respectively), with potassium tetrakis (4-chlorophenyl)borate as an ionic additive, polyvinyl chloride as the matrix material, and dioctyl phthalate as a plasticizer. Between pH 4 and pH 8.5, sensors 1 and 2 exhibited fast, stable, and near-Nernstian responses (58.9 and 57.5 mV/decade, respectively) over an eletriptan concentration range of 10-2-10-6 M; the detection limits were 4 ×10-6 and 6 ×10-6 M, respectively. The selectivity coefficients of the investigated sensors were very low, which indicated that the method was free from interference. The determination of eletriptan content from its dosage form resulted in average recoveries of 97.86% and 100% and mean relative standard deviations of 2.16% and 2.42% for the β- and γ-cyclodextrin sensors, respectively. The determined values were similar to those obtained by an ultraviolet spectrophotometric method. Molecular modeling was used to calculate the host-guest relations between eletriptan and β- or γ-cyclodextrin. The lowest binding free energy was -6.15 and -7.89 kcal/mol for the host-guest complexes with a 1:1 stoichiometry of eletriptan and β- or γ-cyclodextrin, respectively.