A liposomal drug delivery system for improved eradication of Helicobacter pylori

Helicobacter pylori is the leading cause of peptic ulcers and gastric cancer. Eradicating H. pylori infections is becoming more difficult due to increasing antibiotic resistance and poor patient compliance. We aim to develop a novel liposomal drug delivery system that encapsulates antibiotics and the antimicrobial fatty acid linolenic acid (LLA). We hypothesise that H. pylori will have much lower resistance rates to this dual formulation. Liposomes consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), sphingomyelin, and cholesterol were produced using the thin film hydration method. The size of our liposomes was assessed using dynamic light scattering (DLS), and their antimicrobial activity was assessed using a viable count assay. The liposomes had a particle size ranging from 95 to 150 nm. We have successfully loaded LLA up to 20 % of total lipid composition, and shown stability of the particles in storage at 4 °C for up to 3 months. The LLA liposomes achieved complete eradication of H. pylori in vitro at 150 µg ml−1, whereas control liposomes containing no LLA had no antimicrobial effect. We have recently formulated liposomes encapsulating LLA and amoxicillin at 2.2 mg ml−1 and 0.99 mg ml−1 respectively, and are currently assessing their antimicrobial activity against H. pylori. In conclusion, it is possible to prepare LLA- and amoxicillin-containing liposomes and LLA has antimicrobial activity against H. pylori. In future work we will utilise strategies to enhance gastric retention which will provide local bactericidal activity, improving on inefficient systemic uptake mechanisms with current therapies.