Application of dendrimer-drug complexation in the enhancement of drug solubility and bioavailability

Dendrimers are 3D, hyperbranched, tree-like polymers having immense potential in drug delivery, targeting, diagnosis and as carriers for DNA/gene delivery. Dendrimers have hydrophilic exteriors and hydrophilic interiors, which are responsible for its unimolecular micellar nature. They form covalent as well as non-covalent complexes with drug molecules and hydrophobes, which are responsible for its solubilisation behaviour. Dendrimer mediated complexation is advantageous in terms of stability, controlled release, high drug payload and reduced toxicity of entrapped drug(s). Studies on non-covalent interaction of dendrimers with drugs are in abundance so far as solubilisation is concerned. However, the non-covalent complexation often leads to lower drug encapsulation and complex stability compared to covalent conjugation. High drug payload and stability leads to higher bioavailability of the drugs. In addition dendrimers can be surface engineered to release the drug at desired site, that is, as targeted drug delivery. This property along with the solubilisation behaviour could improve the bioavailability of drugs.