Co-Delivery of Teriflunomide and Methotrexate from Hydroxyapatite Nanoparticles for the Treatment of Rheumatoid Arthritis: In Vitro Characterization, Pharmacodynamic and Biochemical Investigations.

Abstract

The present investigation was aimed at developing Teriflunomide (TEF) and Methotrexate (MTX) loaded hydroxyapatite nanoparticles and increasing tolerability towards combination therapy against rheumatoid arthritis by reducing hepatotoxicity. Drug-loaded HAp-NPs were synthesized by wet-chemical precipitation method and optimized by Box-Behnken experimental design. The developed NPs were subjected to in vitro and in vivo characterization. In-vivo pharmacodynamics and biochemical studies were performed on adjuvant- induced arthritis model treated with different formulations; MTX-TEF-SOL, TEF-HAp-NP, MTX-HAp-NP, TEF-MTX-HAp-NP, FOLITRAX-10 and AUBAGIO. The size of the optimized formulations, TEF-HAp-NP and MTX-HAp-NP, was found to be 224.3 ± 83.80nm and 268.3 ± 73.86nm with drug loading 53.11 ± 0.84% and 67.04 ± 1.12% respectively. In vitro release of TEF from TEF-HAp-NP (70.41 ± 1.22%) and MTX from MTX-HAp-NP (82.43 ± 1.31%) up to 24h revealed sustained release pattern. Results of the arthritic assessment study showed a significant (P < 0.05) reduction in ankle diameter (61.30 ± 7.42) and arthritis score (2.35 ± 0.24) with a marked restoration of ankle joint micro-architecture in TEF-MTX-HAp-NP treated group. During Hepatotoxicity studies, liver histopathology revealed that the formulation MTX-TEF-HAp-NP was least hepatotoxic with less hepatocyte swelling and fibrous connective tissue proliferation while Folitrax-10 was found to be most hepatotoxic. Biochemical studies revealed that Folitrax-10 significantly (P < 0.05) increased the GOT (313.64 ± 16) and GPT level (334.46 ± 13) while insignificant (P > 0.05) change in GOT (263.68 ± 17) and GPT (229.38 ± 10) level was recorded with TEF-MTX-HAp-NP. We report that the subcutaneous delivery of TEF-MTX-HAp-NP was most effective as it successfully reduced the dosage by half for maximizing therapeutic efficacy and minimizing side effects. Graphical Abstract ᅟ.