5-Fluorouracil enteric-coated nanoparticles for improved apoptotic activity and therapeutic index in treating colorectal cancer

Abstract

5-Fluorouracil (5-FU) is one among the anti-cancer agents in FOLFORINOX treatment along with oxaliplatin and irinotecan for the treatment of colorectal cancer. Despite its potential activity on the tumor cells, it lacks site specificity partly attributed by its biodistribution to healthy cells resulting in toxic effects to healthy cells. Therefore, we have formulated 5-fluorouracil enteric-coated nanoparticles (5-FUEC) to localize the drug in the colon area that enables its prolonged presence in target area in a sustained manner. The current work emphasizes on enhanced anti-cancer activity of 5-FUEC sequencing its apoptotic activity on HCT 116 colorectal cancer cell lines in vitro. MTT assay exhibited 5.5-fold decrease in IC50 value of nanoparticles comparable to 5-FU. Nuclear fragmentation with irregular edges in nucleus of cells justified its improved activity. Furthermore, flow cytometric analysis confirms the majority of cells gated in early apoptotic (39.75%) and late apoptotic phase (36.25%). Acridine orange/ethidium bromide staining (AO/EB) exhibited cells with red fluorescence (indicating apoptosis) comparable to the control and 5-FU. γ-Scintigraphic studies determined the applicability and feasibility of the enteric coating with mean gastric emptying time, mean intestinal transit time and mean colon arrival time of 1.89 ± 0.03, 2.15 ± 0.05 and 4.03 ± 0.27 h, respectively. Moreover, nanoparticulate approach was found significant in reducing tumor size and volume in xenograft tumor models in vivo along with sustained release. These superior anti-cancer activities exhibited by 5-FUEC indicated that it could be a potential alternative to chemotherapy for colorectal cancer.