Insight to drug delivery aspects for colorectal cancer

Table 2 Receptor based drug targeting for the treatment of colorectal cancer

Ligand	Receptor	Formulations	Bioactives	Remarks	Ref.
Cetuximab (Ctx)	Epidermal growth factor receptor (EGFR)	Magneto-fluorescent silica nanoparticles (MFSN)	-	MFSN-Ctx produced significant MRI signal changes in a human colon cancer xenograft mouse model. The local concentration of MFSN-Ctx in a tumor was amplified by the use of an external magnetic field. MFSN-Ctx can be used for the detection of EGFR-expressing colon cancer using in vivo imaging approaches	[59]
Folic acid (FA)	Folate	Folic acid conjugated guar gum nanoparticles (MTX-FA-GGNP)	Methotrexate (MTX)	MTX-FA-GGNP showed better growth inhibition of Caco 2 cells due to folate receptor mediated uptake. The MTX-GGNP not only protected the release of MTX in upper gastrointestinal tract but also showed maximum release of MTX in simulated colonic fluids (pH 6.8). The in vivo uptake studies revealed preferential uptake of nanoparticles formulation in the colon	[60]
Wheat germ agglutinin (WGA)	WGA receptor	Wheat germ agglutinin (WGA)-functionalised chitosan-Ca-alginate (CTS-Ca-ALG) microparticles (MPs)	5-FU	MPs significantly delivered 5-FU to Caco-2 cells and increased [methyl-³H]thymidine uptake. Gastrointestinal distribution was in favour of increased localization and concentration of the particles in colon region	[1]
Anti-vascular endothelial growth factor (VEGF)-antibody	VEGF receptor	Anti-VEGF antibody-conjugated dextran-coated iron oxide nanoparticles (anti-VEGF-NPs)	-	anti-VEGF-NPs demonstrated in vivo tumor targeting and efficient accumulation in tumor tissues after systemic delivery in a colon cancer model	[61]
Hyaluronic acid (HA)	HA receptor, CD44	HA modified mesoporous silica nanoparticles (HA-MSNs)	Doxorubicin hydrochloride (Dox)	Dox loaded HA-MSNs showed greater cytotoxicity to HCT-116 cells than free Dox and Dox-MSNs due to the enhanced cell internalization behavior of HA-MSNs.	[62]