PT - JOURNAL ARTICLE AU - Higaki, M AU - Ishihara, T AU - Izumo, N AU - Takatsu, M AU - Mizushima, Y TI - Treatment of experimental arthritis with poly(<span class="sc">d, l</span>-lactic/glycolic acid) nanoparticles encapsulating betamethasone sodium phosphate AID - 10.1136/ard.2004.030759 DP - 2005 Aug 01 TA - Annals of the Rheumatic Diseases PG - 1132--1136 VI - 64 IP - 8 4099 - http://ard.bmj.com/content/64/8/1132.short 4100 - http://ard.bmj.com/content/64/8/1132.full SO - Ann Rheum Dis2005 Aug 01; 64 AB - Objective: To examine the therapeutic activity of hydrophilic glucocorticoid encapsulated in PLGA nanoparticles, which have shown slow release and are targeted to inflamed joints after intravenous administration, in experimental arthritis models.Methods: Betamethasone sodium phosphate (BSP) encapsulated in PLGA nanoparticles with a size of 100–200 nm (PLGA-nanosteroid) was prepared using a modified oil in water emulsion solvent diffusion method with Zn ions and coated with lecithin. Rats with adjuvant arthritis (AA rats) and mice with anti-type II collagen antibody induced arthritis (AbIA mice) were treated intravenously with PLGA-nanosteroid after the initial sign of arthritis.Results: In AA rats, a 30% decrease in paw inflammation was obtained in 1 day and maintained for 1 week with a single injection of 100 μg of PLGA-nanosteroid. Soft x ray examination 7 days after this treatment showed decreased soft tissue swelling. Moreover, the PLGA-nanosteroid was also highly effective in AbIA mice. A single injection of 30 μg of the PLGA-nanosteroid resulted in almost complete remission of the inflammatory response after 1 week. In contrast, the same dose of free BSP after three administrations only moderately reduced the severity of inflammation. In addition, a histological examination 7 days after the treatment showed a significant decrease of the inflammatory cells in the joints.Conclusion: The observed strong therapeutic benefit obtained with PLGA-nanosteroid may be due to the targeting of the inflamed joint and its prolonged release in situ. Targeted drug delivery using a sustained release PLGA-nanosteroid is a successful intervention in experimental arthritis.