FIA-spectrophotometric determination of N-substituted phenothiazine derivatives by oxidation with a solid-phase reactor of manganese dioxide incorporated in polyester resin beads

Abstract

The determination of several N-substituted phenothiazine derivatives was carried out by the reaction of the drug with managanese dioxide entrapped in a polymeric material in a packed-bed reactor; the oxidized drug was monitored at λ max. The calibration graph is linear over the range 5–50 μg/ml of phenothiazine derivatives with a relative standard deviation of 0.5–1% (at 10 μg/ml) and sample throughput of 40–48 h −1. The influence of foreign compounds was studied and the method was applied to the determination of six different phenothiazine derivatives in pharmaceutical formulations.