Application of hollow porous molecularly imprinted polymers using K2Ti4O9 coupled with SPE-HPLC for the determination of celecoxib in human urine samples: optimization by central composite design (CCD)†
A novel method is described for trace determination of celecoxib, a nonsteroidal anti-inflammatory drug (NSAID), by hollow porous molecularly imprinted polymer and solid-phase extraction (HPMIP-SPE) coupled with high-performance liquid chromatography with UV detection (HPLC/UV). The synthesis of HPMIPs was performed using a sacrificial support approach with K2Ti4O9 as a sacrificial matrix. Also, methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), chloroform, 2,2′-azobisisobutyronitrile (AIBN) and celecoxib were applied as a functional monomer, cross-linker monomer, solvent, initiator and target drug, respectively. Transmission electron microscopy (TEM) and FT-IR spectroscopy were used for characterizing the synthesized polymers. Also, a central composite design (CCD) under response surface methodology (RSM) was applied to investigate and optimize the extraction procedure parameters such as pH, loading and eluent solvent flow-rate, eluent solvent volume and sorbent mass that probably influence the extraction process to achieve the highest celecoxib extraction efficiency. The following adsorption characteristics investigation exhibited surprisingly higher adsorption capacity (43.29 mg g−1) and faster kinetic binding (25 min) than any previously reported celecoxib imprinted MIPs by traditional or surface imprinting technology. The limit of detection (LOD) and limit of quantification (LOQ) were 0.11 ng mL−1 and 0.25 ng mL−1, respectively. The recoveries (94.73–103.50%) with RSD values lower than 4.74% were relatively satisfactory. The results of the real sample analysis confirmed the superiority of the proposed HPMIP-SPE-HPLC/UV for the selective and efficient enrichment of trace celecoxib from complex matrices.