A new nano particulate vehicle for ultrasound enhanced delivery of Cisplatin

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Chemotherapy for the treatment of cancer continues to make great advances. However the current methods of drug delivery rely on injection into a blood vessel and remain very poorly optimised if at all. This results in having to administer high levels of the drug to the whole body, to give local concentrations in the tumour that are effective in reducing or eliminating the tumour. What this means for the patient is significant side effects such as general debilitation, but also the compounds used can be toxic to the kidneys, liver and nerve tissues. One such compound used is called Cisplatin and is the drug of choice for the treatment of head and neck cancers, which have an unacceptably high mortality rate of over 50%. This high mortality rate is due to a number of factors but one of the main factors is that these particular tumour types are quite aggressive and difficult to treat. Thus to develop a delivery system that gives much higher drug concentrations where it is needed would have significant benefits for both the patient and the healthcare provider. One method to deliver drugs to tumours is to utilise nanoparticles. The reason this potentially can be effective is that blood vessels in tumours are "leaky" and will allow nanoparticles to cross from the blood vessel into the tumour. However even though the nanoparticles cross the blood vessel, the particles can show quite poor uptake by the cancer cells. Thus our system aims to combine a nanoparticle within a microbubble. The idea behind the delivery system is that the nanoparticle trapped within the microbubble are injected and an ultrasound probe is applied to the site of the tumour. As the particles passes beneath the ultrasound probe, the ultrasound bursts the bubble and this produces a small shock wave and this has the effect of forcing the nanoparticle across the blood vessel wall and forcing the particle into the cells of the surrounding tumour. This ultimately will give much more localised delivery of the compound meaning enhanced efficacy and reduced side effects for the patient.