Acridine and its derivatives: a patent review (2009 - 2013).

INTRODUCTION: Acridine derivatives have been extensively explored as potential therapeutic agents for the treatment of a number of diseases, such as cancer, Alzheimer's, and bacterial and protozoan infections. Their mode of action is mainly attributed to DNA intercalation and the subsequent effects on the biological processes linked to DNA and its related enzymes. AREA COVERED: This review covers the relevant efforts in developing acridine derivatives with enhanced therapeutic potency and selectivity and as fluorescent materials, with particular focus on the newly patented acridine derivatives in 2009 - 2013, acridine drugs in clinical trials and preclinical studies, and other new derivatives that emerged in 2009 - 2013. EXPERT OPINION: Thousands of acridines with therapeutic and biological activities or with photochemical properties have been developed. In addition, to modify the position and the nature of the substituent on the acridine core, more attention may be paid to the development of azaacridine or other heteroatom-substituted acridine derivatives and their synthesis methods to broaden the application of acridine derivatives. In cancer chemotherapy, the mode of action of acridine derivatives needs to be further studied. Efficient methods for identification and optimization of acridine derivatives to localize at the sites of disease need to be further developed. Moreover, acridine drugs may be combined with such bioactive agents as DNA repair proteins inhibitors to overcome tumor resistance and improve outcomes.