SINGAPORE (Dec. 23, 10:45 a.m. ET) — Singapore scientists have designed the chemical and physical properties of a new copolymer to target drugs straight to disease sites, improving efficacy and reducing side effects.
Taking a tablet with a sip of water may be the easiest way for a patient to receive drug, but it is not always the most suitable. Some drugs are degraded by the body's metabolism, while others, such as cancer medications, can be more effective if they are delivered directly to the diseased tissue site. Such a delivery could improve the effectiveness of the treatment and potentially reduce side effects.
Yiyan Yang and Jeremy Tan from the A*Star Institute of Bioengineering and Nanotechnology, Singapore, working in collaboration with researchers from the IBM Almaden Research Center and Stanford University in the USA, have prepared biodegradable, water-soluble copolymers that can be loaded with the cancer drug Paclitaxel and injected directly into tumor tissues.
Warming to body temperature causes the drug carried by the polymer to be released. The system shows improvement in killing cancer cells over treatment with the drug alone.
The system works through a careful balance on the nano-scale of the hydrophilic (“water loving” and hydrophobic (“water hating”) properties of the different monomer blocks making up the copolymer.
The scientists' nanoengineering approach also results in copolymers with a narrow distribution of molecular weights – an important factor in producing consistent properties throughout a sample.
Thermoresponsive polymers are not new – one of the most intensively investigated was first synthesized in the 1950s. According to Yang and co-workers, the critical difference between their new materials and previous ones is that the former are both non-toxic and biodegradable.
Yang said: “After these polymers have performed their task of delivering their important cargos, they should break down and be excreted without significant additional side effects. We are now planning further work with the IBM Almaden Research Center and other industrial partners to evaluate the in vivo toxicity and efficacy of this system for delivering therapeutics.”
Yang et al. have reported the work in the peer-reviewed journal Biomaterials: “Thermoresponsive nanostructured polycarbonate block copolymers as biodegradable therapeutic delivery carriers.”