Eudragit S-100 Surface Engineered Nanostructured Lipid Carriers for Colon Targeting of 5-Fluorouracil: Optimization and In Vitro and In Vivo Characterization

5-Fluorouracil (5-FU) is the most preferred chemotherapeutic agent in the management of colon cancer but is associated with poor therapeutic efficacy and lack of site specificity. Hence, it was aimed to employ Eudragit S100 surface engineered 5-FU nanostructured lipid carriers for the spatial and temporal release of the drug for the treatment of colon cancer. Hot high-pressure homogenization (HPH) technique was employed in the preparation of 5-FU-NLCs. The optimization of 5-FU-NLCs was performed using a Quality by Design (QbD) approach. A 3(2) factorial design was employed wherein the relationship between independent variables [amount of oleic acid (X-1) and concentration of Tween (R) 80 (X-2)] and dependent variables [particle size (Y-1) and % entrapment efficiency (Y-2)] was studied. Optimized 5-FU-NLCs were surface treated to obtain Eudragit S100-coated 5-FU-NLCs (EU-5-FU-NLCs). The evaluation parameters for 5-FU-NLCs and EU-5-FU-NLCs included surface morphology, particle size, PDI, and zeta potential. In vitro release from EU-5-FU-NLCs revealed a selective and controlled 5-FU release in the colonic region for 24 h. In vitro cytotoxicity (MTT assay) was performed against Caco-2 cancer cells, wherein EU-5-FU-NLCs exhibited a 2-fold greater cytotoxic potential in comparison to a 5-FU solution (5-FU-DS). Oral administration of EU-5-FU-NLCs in Albino Wistar rats depicted a higher C-max (2.54 folds) and AUC (11 folds) as well as prolonged T-max (16 folds) and MRT (4.32 folds) compared to 5-FU-DS confirming higher bioavailability along with the spatial and temporal release in the colonic region. Thus, a multifaceted strategy involving abridgement of nanotechnology along with surface engineering is introduced for effective chemotherapy of colon cancer via oral administration of 5-FU with uncompromised safety and higher efficacy.