title: Treatment of experimental arthritis with stealth-type polymeric nanoparticles encapsulating betamethasone phosphate.
abstract: We examined the therapeutic activity of betamethasone disodium 21-phosphate (BP) encapsulated in biocompatible and biodegradable blended nanoparticles of poly (D,L-lactic/glycolic acid) (PLGA)/poly(D,L-lactic acid) (PLA) homopolymers and polyethylene glycol (PEG)-block-PLGA/PLA copolymers (stealth nanosteroid) in experimental arthritis models. Various stealth nanosteroids with a size of 45 to 115 nm were prepared and then intravenously administered to rats with adjuvant arthritis (AA) rats and mice with anti-type II collagen antibody-induced arthritis (AbIA). The accumulation of stealth nanoparticles with Cy7 in inflamed joints was determined using an in vivo imaging system. The type A stealth nanosteroid, composed of PLA (2.6 kDa) and PEG (5 kDa)-PLA (3 kDa), with a PEG content of 10% and a diameter of 115 nm, exhibited the highest anti-inflammatory activity. In AA rats, a 35% decrease in paw inflammation was obtained in 1 day and maintained for 9 days with a single injection of the type A stealth nanosteroid (40 microg of BP), whereas the same does of nonstealth nanosteroid and 3 times higher free BP showed a significantly weaker response. In AbIA mice, a single injection of the type A stealth nanosteroid (3 microg of BP) resulted in complete remission of the inflammatory response after 1 week. Furthermore, in AbAI mice, the accumulation of type A stealth nanoparticles in inflamed joints was shown to parallel the severity of inflammation. The observed strong therapeutic benefit obtained with the type A stealth nanosteroid in experimental arthritis may have been due to prolonged blood circulation and targeting to the inflamed joint in addition to its sustained release in situ.
authors.affiliation: Institute of Drug Delivery System, Research Center for Medical Sciences, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ishihara
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Kubota
authors.forename: Tesu
authors.initials: T
authors.lastname: Choi
authors.forename: Megumu
authors.initials: M
authors.lastname: Higaki
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000188:drug therapy*; D001623:Betamethasone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007275:Injections, Intravenous; D019344:Lactic Acid / Q000737:chemistry*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D053758:Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D011917:Rats, Inbred Lew; D014018:Tissue Distribution; D016896:Treatment Outcome
chemical_list: D004337:Drug Carriers; D005938:Glucocorticoids; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols; C028994:betamethasone sodium phosphate; D001623:Betamethasone