Azithromycin-molecularly imprinted polymer based on PVC membrane for Azithromycin determination in drugs using coated graphite electrode

Several molecular imprinted polymer (MIP) membranes for Azithromycin (Azin) coated on graphite electrodes were constructed based on PVC matrix. The Azin-imprinted polymers (MIP) were prepared by thermal polymerization using acrylic acid (AA) and 2-vinyl pyridine (VPY) as monomers, ethylene glycol dimethacrylate (EGDMA) as a cross linker in the presence of benzoyl peroxide (BPO) as an initiator. Two plasticizers di-butyl phosphate (DBP) and di-octyl phthalate (DOP) were used in this study. Electrode parameters such as Nernstian slopes, concentrations, pH and interferences were studied. The results of Azin-MIP electrodes, which based on AA and VPY as monomers with DBP plasticizer, show fully Nemstian slopes. For MIP electrodes using DOP plasticizer the slopes were 49.1 and 51.3 mV/decade, respectively. Excellent detection limits for the electrodes around 10(-7) M were obtained. Life times of MIP were more than four months. The pH range for the electrodes from 3.0 to 8.0 shows no change in the electrode response and a response time around 30 s was noticed for low concentrations of Azin. The effect of some cations and neutral species interferences on electrode response was also studied. Standard addition method using graphite MIP electrode was applied for Azin determination in commercial tablets and capsules of Azin drug. The results obtained by the MIP electrode were compared with the official spectrophotometric method. The binding capacity between polymer of AA as a monomer and Azin as a template was also investigated. (C) 2015 Elsevier B.V. All rights reserved.