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Blood vessels in tumours are irregular in shape, leaky and dilated, and the endothelial cells are poorly aligned and characterised by large fenestrations [1, 2]. As a result, large molecules such as polymers and nanoparticles present in the blood plasma are able to leak into tumour tissue, while being largely restricted from entering normal, healthy tissue [1, 2]. In addition, these large molecules tend to be retained by the tumour mass due to poor lymphatic drainage [1, 2]. This phenomenon, dubbed the EPR effect, provides the rationale for employing high molecular weight ligands to selectively deliver platinum complexes to tumour regions.

Liu et al. have prepared a series of oxaliplatin analogues functionalised with glucose molecules (24–26) [121]. The oxalato ligand of oxaliplatin was replaced with a malonato ligand to provide an extra carbon as an attachment point for the glucose molecule. Similarly to oxalato complexes, malonato complexes are characterised by relatively slow aquation kinetics [127]. In view of this, the glucose targeting group was envisaged to remain bound to the platinum centre in the bloodstream, and only released once inside target cells.

In vivo evaluations in tumour-bearing mice revealed that treatment with (44) resulted in almost three-fold higher platinum accumulation in tumour tissue than the corresponding treatment with the disuccinato platinum(IV) monomer. 2). No comparisons with cisplatin were reported. 15) [169]. Carbon nanotubes possess a number of advantages as drug delivery agents, including excellent cell membrane permeability, long circulating times and intrinsic near-infrared fluorescent properties, which allow their distribution in biological systems to be mapped [169, 170].