“…In those studies, it was reported that the spectral characteristics of drugs are significantly affected by the presence of surfactants (Banipal et al, ; Caetano and Tabak, ; Cudina et al, ; Enache and Volanschi, ; Erdinc et al, ; Gokturk et al, ; Qian et al, ; Rub et al, ). Those reports also confirmed that there are two types of interactions between drugs and surfactants depending on the chemical structure of both drugs and surfactants i.e., at concentrations below the CMC, a decrease in the absorbance with the appearance of a new band indicates the formation of a complex between drug and surfactant molecules, while above the CMC an increase in the absorption coefficient at high micelle concentrations indicates incorporation of drugs into micelles (Caetano and Tabak, ; Cudina et al, ; Enache and Volanschi, ; Erdinc et al, ; Gokturk et al, ). In this context, the binding constants of drugs to micelles can be quantitatively determined using the simple mathematical model known as the Benesi–Hildebrand equation based on the Beer–Lambert law valid in the high micelle concentration region (Benesi and Hildebrand, ).…”