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α-Methylprednisolone conjugated cyclodextrin polymer-based nanoparticles for rheumatoid arthritis therapy

Authors Hwang J, Rodgers K, Oliver JC, Schluep T

Published 12 September 2008 Volume 2008:3(3) Pages 359—371


Review by Single anonymous peer review

Peer reviewer comments 3

Jungyeon Hwang1, Kathleen Rodgers2, James C Oliver3, Thomas Schluep1

1Insert Therapeutics, Inc., Pasadena, CA, USA; 2Livingston Research Institute, Los Angeles, CA, USA; James C Oliver, Peptagen, Inc., Raleigh, NC USA

Abstract: A glycinate derivative of α-methylprednisolone (MP) was prepared and conjugated to a linear cyclodextrin polymer (CDP) with a loading of 12.4% w/w. The polymer conjugate (CDP-MP) self-assembled into nanoparticles with a size of 27 nm. Release kinetics of MP from the polymer conjugate showed a half-life (t1/2) of 50 h in phosphate buffer solution (PBS) and 19 h in human plasma. In vitro, the proliferation of human lymphocytes was suppressed to a similar extent but with a delayed effect when CDP-MP was compared with free MP. In vivo, CDP-MP was administered intravenously to mice with collagen-induced arthritis and compared with free MP. CDP-MP was administered weekly for six weeks (0.07, 0.7, and 7 mg/kg/week) and MP was administered daily for six weeks (0.01, 0.1, and 1 mg/kg/day). Body weight changes were minimal in all animals. After 28 days, a significant decrease in arthritis score was observed in animals treated weekly with an intermediate or high dose of CDP-MP. Additionally, dorsoplantar swelling was reduced to baseline in animals treated with CDP-MP at the intermediate and high dose level. Histological evaluation showed a reduction in synovitis, pannus formation and disruption of architecture at the highest dose level of CDP-MP. MP administered daily at equivalent cumulative doses showed minimal efficacy in this model. This study demonstrates that conjugation of MP to a cyclodextrin-polymer may improve its efficacy, leading to lower doses and less frequent administration for a safer and more convenient management of rheumatoid arthritis.

Keywords: α-methylprednisolone (MP), cyclodextrin polymer (CDP), polymer conjugate (CDP-MP), rheumatoid arthritis (RA), enhanced permeability and retention effect (EPR)

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