Preparation and Evaluation of Exosomes Loaded with Combined Drugs against Colon Cancer

Background:

Nanoscale delivery systems such as milk exosomes, promising carriers for drug delivery, are used to deliver therapeutic drug molecules to the targeted organs. They possess characteristics that include low immunogenicity, specificity, and high bioavailability of cancer drugs. This research study unfolds the influence of the combination of phytoconstituents such as quercetin with an anticancer agent 5-fluoro uracil against the colon cancer cells HCT 116 and epithelial cells NCM 460 in vitro both individually and in combination when loaded into bovine exosomes.

Materials and Methods:

exosomes were isolated from a bovine source using the ultracentrifugation method and lyophilized. The selected drugs were loaded into exosomes by incubation, sonication, and freeze-thaw methods and morphologically characterized by SEM and zeta potential studies, FTIR studies, and in vitro diffusion studies. The study also highlights the in vitro cytotoxicity of the exosomal formulations

Results:

The particle size of the pure exosomes, Exo 5FU and Exo QCT, was determined by Zeta sizer to be 125.7 nm, 157.8, and 142.4 nm, respectively. Further, the mean particle size of (5-FU+QCT) combination-loaded exosomes was 115.8 nm. The freeze-thaw method shows the highest possibility of drug loading. The flux of the release study is almost constant, with a permeability constant of 0.138. Further, the cytotoxicity study showed that Exo-Quercetin has an IC₅₀ value, which is much less than pure Quercetin's IC₅₀ value, indicating better activity.

Conclusion:

The present study indicated the feasibility of isolating exosomes from cow milk exploited in drug delivery systems as they remain unaffected by stomach acids. The exosomes were discrete, uniform, and stable in size. Selected drugs Quercetin and 5-FU and Combination were best loaded in exosomes by the freeze-thaw method. FTIR study showed that there is no or very little interaction as almost all the functional groups are the same in the case of pure drugs and the formulation. The cytotoxicity study showed that drugs loaded into exosomes had better IC₅₀ values than the pure drugs indicating their role as potential applications in cancer therapy by reduced drug doses and minimum side effects.