A coil in the stomach for better TB treatment

The researchers added 600 pills of different formulations to the coil made of a nickel-titanium alloy.Malvika VermaMalvika_Verma  

The treatment of tuberculosis is becoming more difficult as most patients don’t adhere to the treatment regimen which includes six to nine months of daily antibiotics. This also contributes to emergence of multidrug-resistant bacteria.

Now, researchers from Massachusetts Institute of Technology, U.S., have developed a coil loaded with antibiotics that can stay in the stomach for up to a month and release the necessary drugs in the required doses. This eliminates the need for daily administration and also brings down the cost of treatment. The coil is made of a nickel-titanium alloy (nitinol) and looks like a small slinky toy. Just like adding beads on a string, the researchers added 600 pills (4 mm height and diameter) of different formulations to the coil. The drugs used included doxycycline hyclate, isoniazid, ethambutol, pyrazinamide, moxifloxacin, and rifampicin. The pills were spray coated with a special polymer which enabled controlled release of the drug. The final coil measures 32 mm in thickness and when stretched out is around 2 metre in length.

Lab studies

Laboratory studies showed that the coated pills were able to release the drugs slowly for up to one month.

For in vivo studies, the researchers stretched out the coil and inserted it through the nose into a pig’s stomach.

When asked why nasogastric route was used instead of oral, Malvika Verma, the first author of the study said: “As of now, the nasogastric tube is the feasible way to deliver this device since the largest swallowable capsule can only hold 1 gram of drug at most. This tube enables delivery of more than 10 grams of drugs.”

After reaching the stomach, the tube coiled up, stayed in the stomach and released drugs for 28 days. Endoscopic evaluation showed that having such a large coil in the stomach did not cause any injury or ulcer. There was also no weight loss or limitations in the passage of food and water.

The coil can be retrieved via the same nasogastric route by inserting a tube which attaches to the magnet on the coil. Ms. Verma added that further work is being carried out to understand the acceptability and feasibility of the system during insertion and retrieval. The team anticipates initial human trials to begin in the next five years.

The researchers spoke to 300 tuberculosis patients and over 100 TB health providers in India and noted that most of them were open to the idea of a monthly administration using this coil.

“In many cases, this was preferred by the patients, who could come to a health-care setting every two weeks or every four weeks instead of having to be seen by a health care provider every day,” says Prof. Giovanni Traverso from MIT’s Department of Mechanical Engineering in a release. He is one of the corresponding authors of the paper published in Science Translational Medicine. The team also analysed the economic impact of this new treatment regimen and the paper notes that the cost could be reduced by “more than $8,000 per patient”