PREPARATION AND STUDY OF AMOXICILLIN SELECTIVE ELECTRODES AND THEIR APPLICATIONWITH DERIVATIVE SPECTROPHOTOMETER IN PHARMACEUTICAL DRUGS

Amoxicillin trihydrate selective electrodes were prepared based on amoxicillin-phosphotungstate (Amox-PT) as an active sensor with different plasticizers, di-butyl phosphate (DBP), di-butyl phthalate (DBPH), di-octyl phthalate (DOPH), tri-butyl phosphate (TBP) and o-nitro phenyl octyl ether (NPOE) in PVC matrix membranes. The study was carried out to investigate the electrode parameters, effect of pH, selectivity and UV-derivative spectrophotometer technique. Internal filling solution of 10^-3 M + 10^-3 M NaCl was used to fill the electrodes. The best electrode was based on DBP plasticizer which gave a slope 58.7 mV/decade and detection limit of 2 x 10^-6 M displayed good stability and reproducibility. The electrode was used to determine the amoxicillin in oral suspension and capsules. The results were compared with UV-derivative spectrophotometer technique and the recovery for the drugs obtained by second derivative are quite comparable with the recovery obtained by amoxicillin electrodes.