Quality by design (QbD) accredited rutin-loaded self-nanoemulsifying system of krill oil for improved dissolution rate, ameliorating human neuroblastoma and hyperlipidemia.

Rutin (RU) and krill oil (KO) offer antioxidant synergism against free radicals generated during oxidative stress. RU/KO confers anti-hyperlipidemic, anti-inflammatory and pro-apoptotic actions following alternative pathways. However, their poor aqueous solubility/miscibility (RU/KO) affects the dissolution, dispersibility and low bioavailability. We developed a self-nanoemulsifying system (SNE) using a central-composite design (CCD) strategy to improve the nano-dispersibility of KO and RU. Six SNEs were physically evaluated for droplet size, zeta potential and electrical conductivity. Earlier, RU had maximal solubility in Tween80 and PEG600 amongst ternary components investigated to constitute Smix (surfactant cosolvent mixture). Dilution lines (fixed KO/Smix fraction containing PEG600) were traced out to find out one phase region (OPR) at different Smix ratios. Six nanoformulations (NFs) were chosen from the CCD design and had their droplet size in the range of 80-220 nm; electrical conductivity 135-351 μS/cm and dynamic viscosity eta (η) 10-400 mPas. Further, NFs underwent phase transformation following percolation in their nano-structure domains. In-vitro release of RU, characterized in 0.1 N HCl at pH 1.2 and PBS at pH 6.8 demonstrated a significant difference in the amount of RU dissolved compared to coarse emulsion/ powder RU. Interfacial activity of the system resulted from nano-ionization of KO/RU in NF facilitated via the PEG600/Tween80 system. Further, refractive index (non-linear), conductivity (bimodal) supported phase transformation. and difference in RU solubility. During phase transformation, PEG 600 interacts with the aqueous phase in KO/Tween80 system at 1640-1610 cm-1. Out of PEG600/PG/ethanol as solvents, only PEG600 had least conductive domains and had variations in phase dynamic. Preclinical assessment showed that NF (F4) had antihyperlipidemic activity over coarse emulsion as well as plain KO/RU mix (p < 0.01). Furthermore, lipid profile markers (TC, TG, HDL, LDL, and VLDL) were significantly different from F4 vs. control and coarse emulsion upto 15 days administered to animals following a high-fat diet model. Cytotoxicity of NF (F4) in a neuroblastoma cell line (SH-SY5Y) demonstrated inhibition of growth in 100-500× dilution vs. control (coarse emulsion of KO). PEG600 provides RU solubility and induces the phase behaviour of KO enabled one phase region availability and improved dissolution profile of RU. CCD designed RU-loaded SNE of KO-based NFs enhanced the dissolution rate of RU, ameliorating hyperlipidemic activity in animal models and cytotoxic potential in neuroblastoma cell lines.