HPLC quantitation of the four stereoisomers of benzoxathiepin derivatives with cellulose phenyl type chiral stationary phase and circular dichroism detection

The chiral separation of a new antianginal agent has been investigated on a chiral cellulose column with UV and circular dichroism (CD) detection. This benzoxathiepin derivative under development has two stereogenic centers whose (R,S) stereoisomer shows an interesting antianginal activity. After optimisation of the mobile phase composition, a baseline-resolved separation of the four stereoisomers was achieved on a Chiralcel OJ-H chiral column by using methanol–ethanol–diethylamine (25:75:0.1, v/v/v) as mobile phase. The CD detection system allowed quantitation and a linear response was observed within a 10–200 μg mL−1 concentration range (r2 = 0.9966) and limit of quantification down to 2 μg mL−1 was achieved.