The cytotoxicity and photo-enhanced cytotoxicity of a series of 18 3, 6-di-substituted acridines were evaluated on both tumour CHO cells and human normal keratinocytes, and compared to their corresponding clastogenicity as assessed by the micronucleus assay. Compounds 2ftert-butyl N-[(6-tert-butoxycarbonylamino) acridin-3-yl] carbamate and 2dN-[6- (pivalamino) acridin-3-yl] pivalamide displayed a specific cytotoxicity on CHO cells. These ...