pH-sensitive polymeric micelles for targeted delivery to inflamed joints

Area of Science:

• Biomaterials Science
• Nanotechnology
• Rheumatology

Background:

• Rheumatoid arthritis treatment is limited by drugs that cannot selectively target inflamed joints.
• Conventional drug delivery systems like liposomes and micelles can be unstable, leading to uncontrolled drug release.

Purpose of the Study:

• To develop a novel pH-sensitive polymeric micelle system for targeted delivery of prednisolone (PD) to inflamed joints.
• To evaluate the stability, drug release kinetics, and therapeutic efficacy of PD-loaded micelles in a rheumatoid arthritis mouse model.

Main Methods:

• Synthesized amphiphilic conjugates of a PEG-based derivative and prednisolone (PD).
• Formed pH-sensitive polymeric micelles via self-assembly, characterized by drug loading.
• Administered PD micelles intravenously to mice with collagen-induced arthritis and assessed drug distribution, plasma/joint concentrations, and pharmacodynamics.

Main Results:

• PD micelles achieved a drug loading of 19.29% and demonstrated pH-sensitive drug release in acidic environments.
• Intravenous injection of PD micelles resulted in significant accumulation of PD in the joints of arthritic mice.
• PD concentrations in plasma and joints were significantly higher with PD micelles compared to free PD, with 4.63-fold and 2.50-fold increases in AUC and Cmax in joints, respectively.

Conclusions:

• PD micelles show promise as a targeted drug delivery system for inflammatory diseases like rheumatoid arthritis.
• The pH-sensitive micelle system enhances joint drug accumulation and improves anti-inflammatory and disease-modifying effects.