Dual-functional lipid polymeric hybrid pH-responsive nanoparticles decorated with cell penetrating peptide and folate for therapy against rheumatoid arthritis.

Methotrexate (MTX), as a disease modifying antirheumatic drug (DMARD), was first line drug to treat rheumatoid arthritis. However, the severe side effect during long term and high dosage usage limit its application. The aim of this study was to develop dual-functional lipid polymeric hybrid pH-responsive nanoparticles to deliver MTX to inflamed joints selectively. The designed MTX loaded stearic acid-octa-arginine and folic acid decorated poly lactic-co-glycolic acid (PLGA) -PK3-based lipid polymeric hybrid nanoparticles (Sta-R8-FA-PPLPNs/MTX) were composed of PK3, Folate-PEG-PLGA, egg PC, and Sta-R8. The nanoparticles exhibited smooth spherical morphology and particle size of 100-150 nm. The in vitro release study indicated that MTX was released faster in phosphate buffered solution (PBS) of pH 5.0 than that in PBS of pH 7.4 from Sta-R8-FA-PPLPNs/MTX. The cellular uptake study revealed that Sta-R8-FA-PPLPNs/MTX were internalized through folate receptor mediated endocytosis into activated macrophages. Therapeutic effects on adjuvant-induced arthritis (AIA) rats further confirm that Sta-R8-FA-PPLPNs/MTX could be promising against rheumatoid arthritis.