Inhalable Nanoparticle Tuberculosis Treatment Shows Promise in Reducing Therapy Burden

Researchers have developed a new inhalable form of tuberculosis treatment that could significantly reduce the burden of current therapy. The study details the development of an inhalable, immunomodulating, biocompatible nanoparticle system encapsulating rifampin, one of the most important tuberculosis drugs.

Treatment takes many months and involves multiple drugs that can cause serious side effects. Because of this, many patients struggle to finish treatment, which leads to treatment failure and drug-resistant TB. Rifampin works well but has two major drawbacks when taken orally: It can damage the liver and not enough of the drug reaches the lungs, where TB bacteria live.

The researchers developed a new way to deliver rifampin directly to the lungs by inhalation instead of pills by packaging the drug into nanoparticles designed to be breathed in. The nanoparticles have a biodegradable core that holds rifampin, an outer coating that helps them stick to macrophages and a natural molecule on the surface that both improves uptake by immune cells and boosts immune activity.

These particles are specially built to go straight to the lungs and be taken up by lung immune cells called macrophages, which are where TB bacteria hide. They are designed to slowly release rifampin over time, to stimulate the immune system to better fight TB and to reduce drug exposure to the rest of the body, lowering side effects. Because the drug stays in the lungs longer using this form of delivery, treatment might only be needed once a week instead of every day.

The researchers used two different mouse models of TB—one that reflects general TB lung infection, and a second, more severe model that closely mimics human TB lung damage and is harder to treat—to test whether once-weekly inhaled nanoparticles work as well as or better than daily oral rifampin in reducing mycobacterium tuberculosis.

The study found that inhaled nanoparticle treatment delivered rifampin much more effectively to the lungs. Compared to taking rifampin by mouth every day, the inhaled nanoparticles kept higher levels of the drug in the lungs for much longer—up to a week after a single dose.

All studies involving Mycobacterium tuberculosis were conducted in a certified Biosafety Level 3 (BSL-3) facility, the standard laboratory environment required for TB research nationwide. These facilities operate under established federal, state and institutional regulations and include controlled access, specialized ventilation, sterilization and other validated safety procedures.

Reducing treatment frequency could improve adherence, lower side effects and make TB care more accessible worldwide. The next phase of this research will focus on how the nanoparticle can be integrated with other standard TB antibiotics to support combination therapy, the cornerstone of TB treatment.

Rifampin is not just a TB drug; it is also a key medication for other serious lung infections caused by non-tuberculous mycobacteria, such as Mycobacterium kansasii and Mycobacterium xenopi, which are increasingly recognized in the US. These infections often affect people with chronic lung disease and can be difficult to treat.

One major limitation of rifampin is that when taken orally, it strongly activates liver enzymes and this reduces the effectiveness of other important antibiotics, such as azithromycin and clarithromycin, which are cornerstones of therapy for Mycobacterium avium/intracellulare complex (MAC) lung disease. Because of this interaction, rifampin is often avoided, even when it could otherwise help. By delivering rifampin directly to the lungs instead of the whole body, this approach could achieve high drug levels in the lungs while minimizing systemic exposure.

The study's findings appear in the journal Antimicrobial Agents and Chemotherapy.