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September 22, 2009

Drug discovery Improvement and Nanotargeted radiotherapy

1. Cancer and cell biology experts at the University of Cincinnati (UC) have developed a new mass spectrometry-based tool they say provides more precise, cost-effective data collection for drug discovery efforts. It generates fewer false positives and can use 20 times less reagant.

Preliminary studies have shown that the new mass spectrometry tool—known as MALDI-QqQMS (matrix-assisted laser desorption ionization-triple quadruple mass spectrometer)—provides a superior means of measuring the enzyme reactions critical to drug discovery at speeds comparable to currently available high-throughput screening systems at significantly lower costs.

Greis and Rathore have developed a custom high-throughput screening method using a generalized platform. Unlike the commercially available systems that analyze byproducts and coupled reactions, their system directly measures and quantifies the substrate and the end product of the reaction.

They say using mass spectrometry to measure the mass and quantity of the product gives researchers a direct measure of the assay and more reliable compounds to explore, eliminating the chances for molecular interference common with chemiluminescence and fluorescence-based systems.

“Analytically, our mass spectrometry-based application provides superior data and also eliminates the issue of producing high numbers of false results, saving a tremendous amount of time chasing down bad leads on drug targets. And because we are using these non-tagged reagents, it only costs us 3 to 5 cents per sample to run these assays, which is a huge cost savings,” adds Greis. “That can mean the difference between $50,000 and $1 million in reagent costs for a single screening project.”


2. Nanotargeted radiotherapy: Tiny particles of albumin, a protein found in the blood, can be used to carry radioactive isotopes to the site of a cancerous tumour in the body and so avoid many of the side-effects of conventional radiotherapy. The next step is to carry out pre-clinical studies on how well the radiolabelled nanospheres can target tumour cells and to demonstrate by how much therapeutic efficacy might be improved using these drug-delivery agents.



Title: Preparation of human serum albumin nanospheres labelled with 188Re

The aim of this paper is to present a method for the labelling human albumin nanospheres with the short lived beta emitter 188Re. In this method stannous chloride is used as reducing agent and potassium sodium tartrate as transchelation agent. Optimal parameters of the labelling reaction and also, the stability of the radiolabelled nanospheres were established. Under optimal reaction condition, after 45 min. at 75°C, the labelling yields were more than 95%; also, 97% of the 188Re is bound to the albumin nanospheres at 20 h after labelling.



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