Chiral Resolution of Several Phenothiazine Compounds and Trimipramine, A Dibenzazepine Drug on Chiralcel OJ-R

The Chiralcel OJ-R phase was tested on its discriminative properties towards six phenothiazine compounds, namely promethazine, oxamemazine, thiazinamium, ethopropazine, trimeprazine, and dixyrazine, besides one dibenzazepine compound, trimipramine. The effect of changes of the mobile phase upon the resolution of the enantiomers was investigated. Acetonitrile supports a symmetrical peak shape while methanol promotes chiral interactions of the analytes on the stationary phase. Consequently the highest resolutions were mostly found for analyses with ternary mixtures of acetonitrile, an alcohol and aqueous sodium perchlorate solutions. Only the drugs with small substituents on side-chain nitrogen showed generally a satisfactory chiral interaction; promethazine and thiazinamium, the two most resembling analytes, could be baseline separated.