New compound developed for controlled delivery of aspirin

By Sunderarajan

New Delhi: Researchers at the Indian Institute of Science (IISc), Bangalore, have developed a new chemical compound that could be used to deliver aspirin in a controlled manner. The compound can be injected and can carry a large amount of aspirin.

In commonly used pills or patches, aspirin is trapped inside a capsule or a mesh. In the new compound, aspirin is built into backbone of a long polymer chain based on a sugar molecule called Xylitol, which occurs naturally in fruits and vegetables and is used as a sweetener. When delivered into the body, enzymes would break the bond between Xylitol molecule and the drug, resulting in gradual release of the drug into bloodstream.

Aspirin is used for reducing fever and pain. It is also used to lower the risk of heart attack or stroke by preventing clots from forming in blood vessels. However, it has certain side effects. Studies have shown that a gradual release of the drug instead of a rapid single burst can stave them off. Further, if a single chemical compound can keep circulating in the body and release a specified amount of the drug periodically, it would help avoid administering multiple pills at different times.

An advantage of the new compound is that it is totally biodegradable. All the precursors used to make the polymer are endogenous or native to the body. So, there is no accumulation. Besides, Xylitol is relatively unreactive and unlikely to interfere with aspirin’s action.

The new compound represents an important technological development as the scientists have for the first time being able to ensure that Xylitol molecules formed a long straight polymer chain that could be easily dissolved into a gel and thus made injectable.

Over the years, research teams in different parts of the world had been attempting to create such Xylitol based polymers for delivering drugs in a controlled manner. But, they could only get complex mesh like structures. These were difficult to dissolve and made injectable. Consequently, they needed to be implanted into the body surgically. The IISc researchers have solved this problem by using a new technique which involved modifying the reaction conditions.

Mr Kaushik Chatterjee, a member of the research team, mentioned that the timing and dose of the drug delivery can be adjusted by merely tweaking the type of chemical bonds and number of free sites the compound has. “For instance, if someone wanted low doses of aspirin over sustained periods, say weeks, then you may want to have more such bonds that would not degrade so easily’’.

He noted that the polymer can be used for incorporating other drugs also. “The chemistry used for incorporating the Aspirin is by reacting the carboxylate group of the drug with the hydroxyl group of Xylitol to form the ester bond. This strategy can be used to include other drugs also in the backbone like ibuprofen’’. The study has been published in International Journal of Pharmaceutics.

(India Science Wire)