Selective adhesion of nanoparticles to inflamed tissue in gastric ulcers.

PURPOSE: Gastrointestinal deposition of nanoparticles was examined after oral administration to mice suffering from an experimental gastric ulcer model. Local drug delivery could reduce side effects and would be a distinct improvement compared to existing therapeutic approaches, e.g. in the local therapy of Helicobacter pylori.

METHODS

A gastric ulcer was induced to Swiss mice by acetic acid injection. Fluorescent polystyrene particles with a nominal size of 50, 200, and 750 nm were administered orally for 3 or 5 days and particle adhesion in the gastrointestinal tract analyzed.

RESULTS

In the ulcerated regions, an enhanced particle adhesion was observed compared to healthy controls. A size dependency of the deposition was found which further increased with a prolonged treatment period. For 750 nm particles only fair adhesion was observed (control, 2.0 +/- 1.4%; ulcer, 4.5 +/- 0.7% of daily administered particle mass), while already 200 nm particles showed higher binding (control, 2.9 +/- 1.3%; ulcer, 7.8 +/- 1.2%). Highest relative adhesion was found for 50 nm particles (control, 2.8 +/- 1.3%; ulcer, 10.0 +/- 1.5%). The targeting index of gastric ulcer versus healthy control was nearly constant around 2 after 3 days treatment, but increased distinctly for smaller particles after 5 days.

CONCLUSIONS

The use of sub-micron sized carriers holds promise for the targeted delivery of drugs to the ulcerated mucosal areas in the stomach.