Friday, September 23, 2016

mPEG-PCL used for targeted dexamethasone delivery to inflamed joints as part of arthritis treatment research.

PolySciTech division of Akina, Inc. (www.polyscitech.com) provides a wide array of biodegradable block copolymers including mPEG-PCL. Arthritis is a highly prevalent immune disorder which leads to joint destruction. It can be treated with anti-inflammatory agents, such as dexamethasone (a steroidal anti-inflammatory), but systemic application of this drug can lead to side-effects. Injecting the drug locally into joints is problematic as more than one joint may be affected by arthritis. Recently, mPEG-PCL was utilized to generate dexamethasone micelles and injected into an arthritic rat model intravenously. As part of inflammatory process, the vasculature around inflamed tissue becomes very ‘leaky’ and allows for easy passage of nanoparticles into inflamed tissue. This process allowed for preferential uptake of the mPEG-PCL nanoparticles into the inflamed arthritic tissue where the dexamethasone served to reduce inflammation and tissue damage. This targeted delivery allows for treatment of multiple joints from one injection and prevents side effects. This research holds promise for improved arthritis treatment. Read more: Wang, Qin, Jiayu Jiang, Wenfei Chen, Hao Jiang, Zhirong Zhang, and Xun Sun. "Targeted delivery of low-dose dexamethasone using PCL–PEG micelles for effective treatment of rheumatoid arthritis." Journal of Controlled Release 230 (2016): 64-72. http://www.sciencedirect.com/science/article/pii/S0168365916301821.


“Abstract: Glucocorticoid (GC) is the cornerstone therapy of rheumatoid arthritis, but high doses are associated with serious adverse effects. In an effort to improve the efficacy of low-dose GC therapy, we developed a micelle system for targeted delivery to inflamed joints and validated the approach in a rat model of arthritis. Micelles loaded with dexamethasone (Dex) self-assembled from the amphipathic poly (ethylene glycol)-block–poly (ε­caprolactone) (PCL–PEG) polymer via film dispersion, and they were injected intravenously at a dose of only 0.8 mg/kg into rats with adjuvant-induced arthritis. The micelles persisted for a relatively long time in the circulation, and they accumulated preferentially in inflamed joints. Micelle-delivered Dex potently reduced joint swelling, bone erosion, and inflammatory cytokine expression in both joint tissue and serum. PCL–PEG micelles caused only moderate adverse effects on body weight, lymphocyte count and blood glucose concentration, and they weakly activated the host complement system. These results suggest that encapsulating Dex in PCL–PEG micelles may allow for safe and effective low-dose GC therapy targeting inflammatory disorders. Keywords: rheumatoid arthritis; PCL–PEG; Dexamethasone; Side effect”


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