Preparation of Lipid Cubic Liquid Crystalline Nanoparticles of Sinomenine Based on Molecular Dynamics Simulations and Investigation of the Efficacy Against Rheumatoid Arthritis

Sinomenine (SIN) is a promising candidate for the treatment of rheumatoid arthritis (RA). Although it possesses the advantage of being non-addictive, its poor aqueous solubility and low oral bioavailability have limited its clinical application. To address these issues, SIN was encapsulated into lipid cubic liquid crystal nanoparticles (LCNPs) and systematically characterized. Molecular dynamics (MD) simulations were first employed to screen suitable excipients for formulation development. Combined with single-factor optimization and Box-Behnken response surface design, the optimal composition and preparation process were determined. The resulting SIN-LCNPs exhibited a particle size of 149.7 ± 0.9 nm, a polydispersity index (PDI) of 0.223 ± 0.01, a zeta potential of -18.9 mV, and an encapsulation efficiency (EE%) of 92.2%. Spectroscopic analyses confirmed successful incorporation of SIN into the lipid matrix. Pharmacodynamic studies revealed that SIN-LCNPs enhanced targeted drug delivery to inflamed joints, significantly alleviating inflammation and suppressing disease progression in rats. In vivo single-pass intestinal perfusion (SPIP) experiments further demonstrated that SIN was primarily absorbed through the small intestine and that the LCNP carrier effectively improved its intestinal permeability. Collectively, this study provides a novel strategy and theoretical foundation for developing efficient formulations of poorly water-soluble drugs, highlighting the potential clinical application of SIN-LCNPs in RA therapy.