Smart capsules make water-soluble drug delivery possible

Scientists have combined a hydrophobic material polylactic acid and a biodegradable polymer calcium carbonate to encapsulate water-soluble drugs, which make it possible to deliver water-soluble compounds to a certain part of the body.

Researchers from Tomsk Polytechnic University and Queen Mary’s University of London used two-micron capsules that have watertight shells inside of which nanoscale magnets can be embedded, allowing a drug to be delivered to the targeted part of the body. Having reached it, capsules gradually dissolve, releasing the drug outward.

According to the researchers, such measures will assist in the delivery of drugs which consists of proteins and other water-soluble substances used to treat a wide range of diseases including cancer and infectious diseases.

"Some drugs contain components that dissolve rapidly in liquid media. For example, proteins immediately begin to dissolve in water. In recent decades various drug delivery methods have been developed, including polymeric micelles, multi-layer micro-capsules and liposomes".

However, when using these technologies fluids leak into the ‘package’ of our drug. As a result, when it comes into contact with aqueous media in the body, its water-soluble components begin to dissolve and the treatment is not efficient. We were tasked to improve the retention of the loaded cargo inside capsules and prevent the ingress of fluids into them," said the main author Valeriya Kudryavtseva, of the Institute of Physics and Technology.

To address this problem, researchers from the Laboratory of New Medications, RASA Center in Tomsk, headed by Gleb Sukhorukov, Queen Mary’s University of London, together with the colleagues from the Laboratory for Hybrid Biomaterials, Tomsk Polytechnic University, headed by Associate Professor Sergei Tverdokhlebov, the Department of Experimental Physics have proposed for the first time to create a combined ‘package’ for drugs, consisting of calcium carbonate coated with a thin nano-layer of polylactic acid: a biodegradable polymer which TPU scientists apply in the creation of biodegradable implants.

"Earlier there were studies with these materials carried out separately. Our colleagues tried to load drugs either into capsules of polylactic acid or into particles of calcium carbonate. Nobody combined the properties of both materials. We decided to experiment and find out what happens as a result," said Dr Kudryavtseva.

The scientists tried to dissolve the improved capsules which used a combination of these materials in various fluids identical to those found in the human body. The capsules were successfully tested. Thanks to polylactic coating, calcium carbonate did not dissolve under the conditions under which it normally dissolves. The researchers point out they developed an unparalleled technology.