Formulation of a dual drug-loaded nanoparticulate co-delivery hydrogel system and its validation in rheumatoid arthritis animal model

Rheumatoid arthritis (RA), a systemic autoimmune disease that dramatically affects patients' quality of life. Given the intricacy of RA's pathophysiology, no single treatment can completely halt the disease progression. Here, we attempted to treat RA holistically and synergistically by co-delivering methotrexate (MTX), a standard slow-acting anti-rheumatic drug, and phenethyl isothiocyanate (PEITC), a bioactive phytochemical, using a sodium alginate (SA)-pluronic F127 (PF-127) in situ hydrogel formulation. Therefore, in the current study, the co-delivery of MTX and PEITC in the nanoparticulate form could help enhance stability and solubility and facilitate greater penetration in the target arthritic tissues. The fabricated MTX NP and PEITC NE were found to have a minimum particle size, PDI, and good zeta potential. Results from in vitro release studies showed that MTX and PEITC were simultaneously released from the DD NP HG matrix over 6-7 days through diffusion and erosion mechanisms. An intra-articular (IA) injection of DD NP HG dramatically reduced chronic inflammation in adjuvant-induced arthritis (AIA) rats, delayed the onset of bone erosion, significantly reduced synovitis, and down-regulated the inflammatory cytokine expression. Most notably, the co-delivery strategy almost entirely restored the morphological features of the ankle joints of RA rats. The hepatic and renal function tests indicated good biological safety for DD NP HG in RA conditions. Taken together, these findings indicated that DD NP HG could achieve good anti-inflammatory activity and reverse cartilage disruption through a synergistic effect between two nanoparticulate forms of MTX and PEITC, which can effectively improve the drawbacks of their free forms.A nanostructured dual-drug loaded smart hydrogel (DD NP HG) was successfully constructed for the intra-articular delivery of MTX and PEITC to the affected joints of RA.The fabrication of the nanoformulation of both MTX (MTX NP) and PEITC (PEITC NE) aided in mitigating the drawbacks and drug-related side effects of the free form of drugs.DD NP HG markedly suppressed joint inflammation and protect against bone destruction in arthritic rats.This combination approach of PEITC and MTX (DD NP HG) synergistically improved anti-arthritic activity and reduced the adverse side effects in vivo.