Nobuo Izumo | PubMed Health

PubMed2006

[Corticosteroid-loading PLA/PLGA-nanospheres].

We developed nanospheres for the intravenous injection that have had sustained release and targeting to the efficiently anti-inflammation effect. These nanospheres formed by poly(D,L-lactic/glycolic acid) (PLGA) or poly(D,L-lactic acid) (PLA), biodegradability and biocompatibility polymer, that were encapsulated betamethasone phosphate and zinc. Result of experimental inflammation models shown that there nanospheres increased effect by targeting to inflammatory sites and also promoted sustained release of betamethasone phosphate from the nanospheres. Moreover, the effect of nanospheres were stronger than clinical pharmaceutical preparation. We propose that these nanospheres are the pharmaceutical preparation to have efficient powerful inflammation action.

Adrenal Cortex Hormones↗

PubMed2005

Role of zinc in formulation of PLGA/PLA nanoparticles encapsulating betamethasone phosphate and its release profile.

The purpose of this study was to develop poly(D,L-lactic/glycolic acid) (PLGA) or poly(D,L-lactic acid) (PLA) nanoparticles of less than 200 nm in diameter that encapsulated water-soluble corticosteroid derivatives for sustained release and targeting to inflammatory sites. Nanoparticles were prepared with PLGA (or PLA), zinc, betamethasone phosphate and surfactant by an oil-in-water solvent diffusion method. With this method, the efficiency of encapsulating betamethasone phosphate in the nanoparticles and the particle size were significantly affected by various factors, such as the concentration of PLGA (or PLA) and the amount of zinc added. Nanoparticles ranging from 80 to 250 nm in diameter could be prepared, with a maximum betamethasone phosphate content of 8% (w/w). Betamethasone phosphate was gradually released from the nanoparticles in diluted serum, and the release rate depended on the glycolic/lactic acid ratio and on the molecular weight of PLGA or PLA. Betamethasone was gradually released over at least 8 days from murine macrophages that had internalized betamethasone phosphate-encapsulated nanoparticles in vitro, and the rate of release was slower than from nanoparticles prepared without zinc. These results suggest that zinc increases the efficiency of encapsulating betamethasone phosphate in nanoparticles and also promotes sustained release of betamethasone phosphate from the nanoparticles.

Animals↗