A QbD strategy to develop curcumin and siRNA co-loaded lipoplexes to combat osteoarthritis-related inflammation and oxidative stress

Chronic knee and lower back pain due to osteoarthritis (OA) has a global prevalence and impacts human well-being by impairing mobility. Oxidative stress and inflammation are key factors in OA pathogenesis and progression. Non-viral gene delivery through liposomes is a promising approach for repairing damaged cartilage tissues. Our study focuses on developing co-loaded lipoplexes for efficient co-delivery of curcumin and therapeutic siRNA. Curcumin downregulates many inflammatory cytokines, scavenges free radicals, and upregulates collagen and aggrecan, therefore reducing pain and helping with regeneration. Quality by Design (QbD) principles guided the development of curcumin-loaded cationic liposomes (CL), which were further used as vectors for therapeutic siRNA in the design of the co-loaded lipoplexes. QbD steps involved risk assessment, Design of Experiments (DoE), and selection of the optimal vector, i.e., optimum curcumin-loaded cationic liposomes (Opt-CL), which would ensure the best transfection efficiency for therapeutic siRNA. The efficiency of Opt-CL was evaluated in both the primary chondrocytes and cell lines, which were induced by oxidative stress and inflammatory conditions. The Opt-CL successfully reduced the oxidative stress levels in both. The Opt-CL were complexed with the IL-6 and IL-8 siRNA to form co-loaded lipoplexes, which efficiently reduced the inflammation in the chondrocytes. These co-loaded lipoplexes effectively transfected chondrocytes with no toxicity and are promising for further testing in OA models. The study has yielded an optimal non-viral vector that could serve as a platform for the incorporation of other lipophilic drugs and negatively charged oligonucleotides for various ailments. HighlightsO_LIUtilization of QbD to screen and optimize critical factors for the development of CL C_LIO_LIDevelopment of proof of concept using the curcumin and luciferase siRNA as the small molecule and oligonucleotide candidates for efficient cell viability and transfection C_LIO_LIEvaluation of cell internalization and gene knockdown in a luciferase-expressing chondrocyte cell line to prove the model efficacy C_LIO_LIIn chondrocytes, the optimized formulation demonstrated the reduction of inflammation and oxidative stress. C_LI