FIA-SPECTROPHOTOMETRIC DETERMINATION OF N-SUBSTITUTED PHENOTHIAZINE-DERIVATIVES BY OXIDATION WITH A SOLID-PHASE REACTOR OF MANGANESE-DIOXIDE INCORPORATED IN POLYESTER RESIN

The determination of several N-substituted phenothiazine derivatives w as carried out by the reaction of the drug with manganese dioxide entr apped in a polymeric material in a packed-bed reactor; the oxidized dr ug was monitored at lambda(max). The calibration graph is linear over the range 5-50 mu g/ml of phenothiazine derivatives with a relative st andard deviation of 0.5-1% (at 10 mu g/ml) and sample throughput of 40 -48 h(-1). The influence of foreign compounds was studied and the meth od was applied to the determination of six different phenothiazine der ivatives in pharmaceutical formulations.