Amoxicillin-Loaded Sponges Made of Collagen and Poly[(methyl vinyl ether)-co-(maleic anhydride)] for Root Canal Treatment: Preparation, Characterization and In Vitro Cell Compatibility.

The difficulty of eliminating Enterococcus faecalis and other bacteria infecting dental root canals makes it desirable to develop formulations capable of sustained release of antibiotics within the canal. With this function in view, in this work we compared the mechanical, drug release and biocompatibility properties of amoxicillin-loaded collagen (CL) and CL complexed with poly[(methyl vinyl ether)-co-(maleic anhydride)] (PVMMA), with or without glutaraldehyde (GTA) or the natural product genipin (GN) as cross-linker. Collagen was not denatured by complexation with PVMMA. Only CL-PVMMA-GN sponges did not disintegrate during 7 days exposure to cell culture medium (un-cross-linked CL disintegrated within 24 h and un-cross-linked CL-PVMMA within 4 days), and CL-PVMMA-GN sponges also exhibited the most appropriate combination of mechanical properties (hardness, modulus of deformability and plasticity). CL-PVMMA-GN sponges absorbed aqueous medium faster than other cross-linked formulations, but their maximum uptake was less; and drug release from CL-PVMMA-GN sponges tended to be faster than from any other, except un-cross-linked CL-PVMMA, maximum release taking about 4 days. No formulation significantly altered the viability of L929 fibroblast-like mouse connective tissue cells, but cells growing on sponges showed signs of non-adherence. It is concluded that genipin-cross-linked CL-PVMMA sponges merit further investigation as antibiotics vehicles and aids to tissue regeneration in the dental root canal.