Researchers at the University of Seville (US) and Hacettepe University of Ankara (Turkey) have confirmed that a cancer drug called paclitaxel is more effective and less aggressive if administered with nanometric capsules of a compound produced from starch. The results obtain so far open the possibility of starting clinical trials to confirm its effectiveness in patients.
The nanoparticles tested have a thousand times smaller diameter than the thickness of a hair. They contain the drug inside, and are administered intravenously to the patient. In the study, published in Beilstein Journal of Nanotechnology, the researchers examined the delivery system in mouse and human cell lines. The results confirm the suitability of the starch nanocapsules to delivery paclitaxel in breast cancer, since they increase the drug’s duration of action and decrease its toxicity.
One goal of the study was to get nanoparticles of less than 200 nanometers in diameter. However, the results obtained from studies have been even better, as they have succeeded to get nanoparticles of 80 nanometers using ethanol as the organic solvent in their formation.
“The size of the capsules in which the medication is delivered is important to improve the outcomes,” said US researcher Carmen Ortiz Mellet, author of the article.
Paclitaxel has been an effective tool since the 70s for the treatment of lung, ovarian and breast cancers. “We were able to confirm that all the nanoparticles we have created are not toxic in mice and its anti-cancer effect increases in cell lines of human breast cancer compared to other administering systems for the drug. Furthermore, the active ingredient is stable in aqueous solution for 30 days,” Ortiz Mellet added.
Safer and more efficient chemotherapy
The coating used to contain the drug is a cyclodextrin derivative, a compound produced from starch widely used in food and pharmaceutical products, as it increases the solubility due to its hydrophilic exterior, i.e. it is soluble in water. However, in its inner cavity, these molecules are hydrophobic (fluid repellent), allowing them to transport the active ingredient to the desired place without releasing it prematurely. They also protect the contents from oxygen and radiation, evenly extended-releasing the drug.
This allows solving some of the most common problems related to chemotherapy medication bioavailability, i.e. the effectiveness in targeting cancer cells and in maintaining their properties during their action. According to experts, research should be directed towards obtaining more permeable molecules to allow drug transport to its target, increased stability in the presence of certain enzymes or other acidic or basic environments, better solubility of the active ingredient in the action site and no in healthy cells, and complete drug release.
During the work it has been shown that the cyclodextrin is capable of modifying the release profile of the encapsulated drug and keep it stable for up to 30 days, confirming the increased bioavailability of paclitaxel and reduction of adverse effects, including decreased white blood cells, hair loss and nausea.