Spectrophotometric Determination of Nitroxoline in Pharmaceuticals in a Cetylpyridinium Chloride Micellar Medium Using Response Surface Methodology and Box-Behnken Designs

This report describes employment of response surface methodology and Box-Behnken designs in developing a spectrophotometric procedure for estimating nitroxoline in a micellar matrix based on cetylpyridinium chloride using a binary dimethyl sulfoxide:water solvent. The intensity of the absorption band at 448 nm was used as the target function. Independent factors were the cetylpyridinium chloride concentration, the pH of the medium, and the dimethyl sulfoxide volume fraction. Amathematical model and pairwise response surfaces with predictive value were constructed. Use of a desirability function yielded the optimal matrix for determining nitroxoline contents: a cetylpyridinium chloride concentration of 4.1 × 10^–3M pH 7.6 and a dimethyl sulfoxide volume fraction of 0.4. This composition gave a linear calibration relationship over the concentration range 0.070–2.550 mg/ml and could be used to assess nitroxoline contents in medicines. Employment of the response surface methodology for estimating nitroxoline in medicines allowed a sensitive and selective technique using a micellar medium based on cetylpyridinium chloride and a spectrophotometric method of analysis to be developed.