Either of the two diastereoisomers of 1-acetyl-4-(4-{[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy}phenyl)piperazine in which the imidazol-1-ylmethyl group and the aryloxymethyl group are in a trans relationship to each other - i.e. they are on opposite sides of the plane of the dioxolane ring. (N.B. The antifungal drug ketoconazole is a racemic mixture of the two cis diastereoisomers.)