Abstract

In this study, a simple and eco-friendly spectrophotometric method was developed for the determination of dapsone (DAP) in pharmaceutical formulations using an ion-pair cloud point extraction (IP-CPE) approach. The IP-CPE method is based on the coupling reaction of dapsone with salbutamol (SUB) in an alkaline medium, producing a stable orange DAP-SUB azo dye with a maximum absorption wavelength at 457 nm. This is followed by the formation of ion-pair associates between the negatively charged DAP-SUB dye and the cationic surfactant CTAB. Triton X-114 was then employed as a non-ionic surfactant to facilitate the cloud point extraction (CPE) procedure. The method exhibited a linear range of 0.25–6 mg/L, with limits of detection (LOD) and quantification (LOQ) of 0.0808 mg/L and 0.245 mg/L, respectively. Good sensitivity was achieved, with a distribution ratio (D) of 3.22 and a preconcentration factor (PF) of 20. Salbutamol was used as a green reagent according to the PBT (persistent, bioaccumulative, and toxic) criteria, and only a small volume of ethanol was required for desorption, significantly reducing solvent waste. The IP-CPE method was further validated using environmental assessment tools BAGI, CACI, and AGREES, all of which confirmed its compliance with green analytical chemistry principles. Overall, the proposed method provides a simple, low-cost, environmentally friendly, and accurate procedure for the preconcentration and determination of dapsone.

Keywords: dapsone, salbutamol, green reagent, Triton X-114, BAGI, CACI, AGREES

Article language: En.