Transdermal patches loaded with etoricoxib nanocrystals as a remedy and prophylactic approach against progression of knee osteoarthritis

Osteoarthritis (OA) is a heterogeneous and multifactorial disorder that affects the entire joint organ. It is a major global public health concern, impacting more than 500 million individuals worldwide. The onset and progression of OA are driven by a complex interplay of factors and modifiable risks such as obesity and joint injury. Consequently, OA imposes a substantial burden on patients' quality of life and on society, owing to increased healthcare expenditures and reduced work productivity. The purpose of this study is to assess the therapeutic efficacy of transdermal patches loaded with etoricoxib nanocrystals (ETX-NCs, previously prepared and evaluated) in the treatment and reduction of osteoarthritis exacerbation. ETX-NCs patches of various polymers were prepared using solvent evaporation technique. The prepared patches were evaluated for drug content, thickness, moisture uptake, folding endurance, in vitro drug release, and skin permeation properties. The prepared patches based on HPMC, CMC Na, and PVA demonstrated uniformity, flexibility, smooth surface morphology and high drug content, along with acceptable physicochemical properties. Among these, the CMC Na based nanocrystal patches exhibited the most prolonged drug release (73.76 ± 2.38%). HPMC and CMC Na based patches showed promising skin penetration of 79.64 ± 1.20 μg/cm² and 44.06 ± 2.72 μg/cm², with corresponding flux values of 16.13 ± 0.21 μg/cm²/h and 8.08 ± 0.47 μg/cm²/h, respectively. Based on in vivo findings, the prepared ETX-NCs patches found to successfully alleviate OA symptoms within short duration (5 days), also protecting against disease progression.