Buccal delivery of low molecular weight heparin by cationic polymethacrylate nanoparticles.

Buccal delivery seems to be a very promising administration route for macromolecular drugs. Here, we explored the potential of cationic polymethacrylate nanoparticles (NPs) as a carrier system for the buccal delivery of low molecular weight heparin (LMWH). LMWH-loaded NPs were prepared by emulsification solvent diffusion method and the NPs were analyzed for their physiochemical properties, rheological evaluations and ex vivo transport studies across buccal mucosa. The prepared LMWH-loaded NPs showed a mean diameter between 400 and 500nm with unimodal size distribution with negative surface charge. Viscosity measurements revealed a positive rheological synergism between the prepared NPs and mucin when mixed under physiological conditions. After 4h, about 6.3±0.9% of LMWH was released in case of using Eudragit RS (ERS); while Eudragit RL (ERL) NPs released only 3.0±0.3 % of its LMWH content and this incomplete release was slightly ameliorated in the presence of mucin reaching to 7.2±0.3 % and 4.8±0.3 % for ERS and ERL, respectively. The ex-vivo permeability of heparin through the buccal mucosa was significantly increased after using polymetharylate NPs while no heparin permeation was detected from free heparin solution. Confocal laser scanning microscopy (CLSM) imaging indicated the mucoadhesive properties of the polymetharylate NPs where the drug-free NPs were detected in the superficial layers of buccal mucosa. LMWH-loaded NPs had less mucoadhesive properties showing significant deeper penetration of the mucosa. The results indicated that mucoadhesive cationic polymethacrylate NPs offer a possible approach for the buccal delivery of heparin.