Colon-Targeted Sustained-Release Combinatorial 5-Fluorouracil and Quercetin poly(lactic-<i>co</i>-glycolic) Acid (PLGA) Nanoparticles Show Enhanced Apoptosis and Minimal Tumor Drug Resistance for Their Potential Use in Colon Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide, acting as a significant public health problem. 5-Fluorouracil (5-FU) is a key chemotherapy for various types of cancer, due to its broad anticancer activity. However, the emergence of drug resistance is a considerable limitation in the clinical application of 5-FU. Quercetin (QC) is proposed as an adjuvant therapy to minimize drug resistance to chemotherapeutics and enhance their pharmacological efficacy. The oral delivery of 5-FU and QC is challenged by poor aqueous solubility of QC and poor cellular permeability of 5-FU. To solve this issue, novel polylactide-<i>co</i>-glycolide (PLGA) combinatorial nanoparticles loading 5-FU and QC were prepared to deliver them directly to the colon. These sustained-release combinatorial nanoparticles recorded a significant decrease in cancer cell proliferation, C-reactive protein (CRP) level, and Interleukin-8 (IL-8) expression by 30.08%, 40.7%, and 46.6%, respectively. The results revealed that this combination therapy may offer a new strategy for the targeted delivery of chemotherapeutics to the colon.