Our Facebook account

Roza F. Bakeeva*, Svetlana Yu. Mamykina, Sergey Yu. Garmonov

Author affiliations
Kazan National Research Technological University, Department of Analytical Chemistry, Kazan, Russia
*Corresponding author: gurf71@mail.ru

Abstract
The results of applying the response surface methodology and experimental design to create an optimal micellar matrix for determining the content of nitroxoline (NX) in dosage forms are presented. The sodium dodecyl sulfate (DSN) system in the binary solvent dimethyl sulfoxide + water (DMSO + H₂O) was used as a micellar matrix. Tensiometric and conductometric methods showed a twofold increase in the critical micelle concentration (CMC) of DSN upon introduction of DMSO. Three-level Box–Behnken plans were used in the work. The intensity of the NX absorption band at 450 nm (A₄₅₀) was chosen as a target function for determining the NX content, since it is proportional to the NX concentration. The main independent factors influencing the target function A₄₅₀ are the surfactant concentration (CDSN, mol/L), pH of the medium, and the proportion of DMSO (αDMSO). Optimal conditions for NX determination are C_DSN = 0.0189 mol/L; pH = 7.6; αDMSO = 0.4. Under these conditions, in the region of close to CMC, a 20-fold increase in the molar extinction coefficient to 35448 L * cm^-1 * mol^-1 is observed, which made it possible to develop a sensitive and rapid method for spectrophotometric determination of NX with good metrological characteristics.

Keywords: spectrophotometry, nitroxoline, micelles, sodium dodecylsulfate, dimethyl sulfoxide, response surface methodology, Box – Behnken plans