Dendrimer therapeutics: covalent and ionic attachments

This concise review focuses on dendrimers functionalized by different linkers required for covalent and ionic attachments of drugs to the dendrimer's surface and highlights the importance of the chemical nature of linkers for controlled release of free drugs. The stability of linkers under physiological conditions and their lability under acidic conditions such as those of endosomes and lysosomes or under enzymatic conditions will be discussed. Especially, we review functionality of the most recently reported drug-dendrimer conjugates. Then, we give a short comparison of dendrimer conjugates versus either dendrimer complexes or polymer therapeutics and finally we briefly summarize the importance of both targeted and nontargeted covalently conjugated drugs.