Plastic pethidine hydrochloride membrane sensor and its pharmaceutical applications

A novel plastic poly (vinyl chloride) membrane electrode based on pethidine-phosphotungstate ion association as electroactive material for the determination of pethidine hydrochloride in injections and tablets is developed, in which the plasticizer is o-nitrophenyl octyl ether. The linear response covers the range of 5×10−6–1×10−2 M drug concentration with a slope of 56.69 mV per decade. The practical pH range is 1–8. The lower detection limit is 8.20×10−7 M. Interferences from common cations, alkaloids and drug excipients are reported. The proposed electrode has been successfully applied to determine pethidine hydrochloride in tablets and injections and content uniformity of tablets. The results are correlated well with those obtained by the USP standard procedure.