Development of an enteric-coated, layered multi-particulate formulation for ileal delivery of viable recombinant Lactococcus lactis

Layering of recombinant hIL-10 producing Lactococcus lactis (L. lactis Thy12) on inert carriers is a promising technique for the preparation of a multi-particulate formulation of viable, hIL-10 producing L. lactis. To improve viability after layering and storage, L. lactis Thy12 was layered in different matrices (10% skim milk and/or 2.5, 5, 10% inulin). After layering, the highest viability was obtained in the 10% skim milk supplemented with 5% inulin matrix (8.7%). However, upon storage, 10% skim milk alone yielded the highest viability. Thereby, layered L. lactis Thy12 showed superior long term stability in comparison with freeze-dried L. lactis Thy12. The layering process was performed during 3 h without encountering technical problems, with good layer consistence and constant viability. Enteric properties were obtained with a 30% Eudragit® L30D-55 or 15% Eudragit® FS30D coating and maintained during an initial six months storage period (−20 °C/20% RH). After in vitro simulation of the gastric stage, only 5% of the bacteria remained viable in Eudragit® L30D-55 coated pellets, contrary to 85% in Eudragit® FS30D coated pellets, indicating its superior protective capacity against gastric fluid. After eight months storage (−20 °C), 80% of the initial L. lactis Thy12 remained viable in the Eudragit® FS30D coated pellets.