Effect of solid nanoparticle of indomethacin on therapy for rheumatoid arthritis in adjuvant-induced arthritis rat.

We designed new oral formulations containing indomethacin (IMC) solid nanoparticles, and investigate their usefulness by evaluating bioavailability and gastrointestinal lesions. The IMC solid nanoparticles were prepared using methylcellulose (MC), 2-hydroxypropyl-β-cyclodextrin (HPβCD), and the bead mill method, and high quality dispersions containing 1.0% IMC nanoparticles were prepared (IMC(nano), particle size: 76 ± 58 nm, means ± S.D.). The fate of serum IMC and the induction of paw edema in adjuvant-induced arthritis (AA) rats receiving low-doses IMC(nano) (0.4 mg/kg) were similar to those following the administration of a therapeutic dose of conventional IMC prepared with MC and HPβCD (conventional IMC, 2 mg/kg), and the bioavailability in 0.4 mg/kg IMC(nano) was 5.3-fold higher in comparison with that in 2 mg/kg conventional IMC. IMC-induced gastrointestinal lesions in AA rats administered IMC(nano) (8 mg/kg), in consideration of bioavailability, were significantly less than for conventional IMC (40 mg/kg). On the other hand, the toxicity caused by conventional IMC and IMC(nano) was similar in Caco-2 cells. It is possible that the oral administration of IMC solid nanoparticles will show increased effectiveness in treating RA without causing IMC-induced gastrointestinal lesions, since the bioavailability is higher than that of conventional IMC. An oral drug delivery system using drug nanoparticles may expand the usage of NSAIDs for therapy in the inflammatory field.