Assay of Famotidine in Pure Solutions and Pharmaceutical Preparatives using the Coated- graphite Electrode as a Detector in the FlA System

A simple electrochemical method was developed to estimate famotidine (FMT) in pure solutions and pharmaceutical preparatives by a flow-injection analysis system (FlA). This method includes preparation of a coated graphite electrode using FMT with the Phosphotungstic acid precipitant (PTA), di-butyl phthalate (DBP) and poly vinyl chloride (PVC). The electrode characteristics were examined by studying the optimum conditions, the carrier current, the injected model size, flow rate, the reaction coil length, pH, the range of concentrations, the minimum Nernst response, the response time, the detection limits, and the study also included identifying the electrode selectivity of the toward other interfering ions. The electrode showed that the best Nernst slope for the calibration curve was at 33.82 mv/decade within linear range of (1.0 × 10-6- 1.0 × 10-1M), correlation coefficient (R2) 0.9999, response time 10 seconds, the estimating speed is 90 sample/hour, while the rate of dilution degree (D) is 2.6452. The obtained results confirmed that it is of high accuracy and precision (Err 0.119%), (Rec 100.11%), (RSD 0.1233%). The proposed method was successfully applied to assay of FMT in commercial tablet forms.