Starchy aid to cancer
doi:10.1038/nindia.2011.169 Published online 21 November 2011
Researchers have designed a new kind of super-paramagnetic starch nanoparticle that is capable of delivering the anticancer drug cisplatin to target cancer cells. The nanoparticle enhances the efficacy of cisplatin and reduces its toxicity to normal cells.
Cisplatin, despite its efficacy for treating cancers of the ovaries, testicles and bladder, triggers harmful effects such as anaemia, nausea and vomiting. In addition, cisplatin is toxic to kidney and nerve cells. An alternative method of administering cisplatin is therefore needed to overcome its toxicity.
Starch is a naturally occurring biodegradable and inert carbohydrate. To explore the potential of starch for delivering cisplatin, the researchers prepared magnetic starch nanoparticles containing iron oxide and then used epichlorohydrin to secure the structure by cross-linking, which increased their drug-loading capability.
The researchers then loaded the magnetic starch nanoparticles with cisplatin and carried out drug-release studies in phosphate buffer solution, with and without the presence of a magnetic field. The varying pH of phosphate buffer solution closely mimics the physiological conditions of blood and the small intestine.
The results indicated that drug release increased when drug loading was less than 20%. This increase occurred because higher drug loading facilitates the faster movement of any phosphate buffer solution that penetrates the nanoparticle surface.
However, when drug loading was more than 20%, drug release was found to decrease. The researchers say that this decrease occurs because the voids of the nanoparticles shrink when they are loaded with drug molecules, which inhibits the diffusion of water molecules into the loaded nanoparticles. Drug release was faster at acidic pH than basic pH. Increasing the magnetic field and temperature increased drug release. Furthermore, the nanoparticles showed no toxic effects on mouse fibroblast cells.
"This method introduces the possibility to magnetically control the release of anticancer drugs at the tumour site while sparing normal cells," says lead researcher Anil K. Bajpai.
Sweta, L. et al. Magnetically controlled release of cisplatin from superparamagnetic starch nanoparticles. Carbohydr. Polymer. 87, 300-308 (2012) | Article |