Artemisinin emulgel ameliorates cartilage degradation in knee osteoarthritis: <i>in vitro</i> and <i>in vivo</i> studies

<b>Aim:</b> Laboratory scale-up of artemisinin-loaded emulgel (ART-emulgel) was carried out and characterized for therapeutic performance in osteoarthritis (OA). <b>Materials &amp; methods:</b> The solubility of ART in various oils, surfactants and co-surfactants were screened for construction of pseudo ternary phase diagram (TPD), followed by scale-up of artemisinin loaded nanoemulsion (ART-NE). ART-NE was amalgamated with Carbopol Ultrez 10-NF to prepare ART-emulgel that was later characterized <i>in vitro</i> and <i>in vivo</i> to analyze therapeutic efficacy in monosodium-iodoacetate (MIA) induced knee OA. <b>Results:</b> The droplet diameter of ART-NE was estimated to be 104.3 ± 2.593 nm with a polydispersity index of 0.245 ± 0.019 in addition to ζ-potential of 0.434 ± 0.028 mV. Steady-state flux and permeability coefficient for ART-emulgel were estimated to be 0.651 ± 0.031 µg.cm²/h and 0.245 ± 0.011 cm/h, respectively. ART-emulgel demonstrated 43.18% reduction in COX-2 level; 52.28% drop in IL-1β, and 88.78% alleviation of Tumor Necrosis Factor-α (TNF-α) level when compared with monosodium-iodoacetate induced OA rats. ART-emulgel and injectable ART (intra-articular; I.A) portrayed minor synovial erosion compared with blank and diclofenac emulgel. Histopathological evidences indicated restoration of cartilage integrity followed by reduction of OARSI scores in ART-emulgel when compared with disease control animals. <b>Conclusion:</b> ART-emulgel is a potential dosage form for translating into a clinically viable product for the management of OA. Artemisinin (ART) has shown critical role in the management of osteoarthritis ART-emulgel owing to submicron size demonstrated high dermal permeation by following the transappendageal pathway ART-emulgel reduces COX-2 expression in addition to TNF-α and IL-1β in experimental osteoarthritic rats. Histopathological analysis revealed restoration of cartilage integrity in ART-emulgel treated group