Nanoparticle-based oral delivery systems for colon targeting: principles and design strategies

Colon-targeted oral delivery is crucial for the treatment of colon-related diseases, as this delivery strategy enables precise drug administration to the diseased site, enhances drug bioavailability, and improves patient com- pliance. In particular, nanoparticle-based oral formulations shield drugs from the harsh gastrointestinal environment, and selectively increase drug colon cells, thus elevating concentration inside diseased therapeutic efficacy while reducing systemic toxicity. In this review, we elaborate recent progress in this area, with emphasis on the patho- physiological characteristics of colon site and design strategies to take advantage of these characteristics for colon targeting.

Targeted therapeutic effects of oral magnetically driven pectin nanoparticles containing chlorogenic acid on colon cancer

Oral colonic nano-drug delivery system has attracted growing attention in treating colon cancer for their excellent characteristics.However,the unique and complex structure of the gastrointestinal tract is still an obstacle to the safe delivery of drugs targeting sites in colon tumors.Here,we designed magnetically driven dual-targeted oral colonic nanoparticles loaded with chlorogenic acid using pectin and oleic acid-modified iron oxide(Fe3O4@OA).Specific degradation of pectin by pectinase produced by colonic flora and magnetic fields applied to the colon confers specific targeting of nanoparticles to the colon.In order to overcome the challenge of preparing magnetically driven nanoparticles with small and homogeneous particle sizes by a single conventional method,we developed the combined ultrasound-emulsification technique.The average particle size of the prepared nanoparticles was 81.04±1.02 nm,which showed good drug release in the simulated colonic environment.In vitro anticancer studies,the drug-loaded nanoparticles possess an obvious toxicity and apoptosis-inducing ability against cancer cells.Meanwhile,the hemolysis results demonstrated the safety of the nanoplatform(PET/CGA/Fe_(3)O_(4)@OA).This work holds broad prospects as a new treatment modality for colon cancer.

Microenvironment responsive pod-structured astaxanthin nanocarrier for ameliorating inflammatory bowel disease

Anti-inflammatory drugs targeting inflammatory bowel disease(IBD)have attracted considerable attention but still face low therapeutic outcomes and frequent side effects.Astaxanthin(ATX),a natural ketone,possesses potent antioxidant and anti-inflammatory properties.However,it faces problems such as poor water solubility,photothermal instability,and low bioavailability.Here,we employed a supramolecular encapsulation strategy to create a nanoscale oral delivery system for ATX(referred to as FC-ATX NPs)by coupling fucoidan(FUC)with chitosan oligosaccharides(COS).The obtained FC-ATX NPs exhibited a particular“bean pod”structure with uniform size,good encapsulation efficiency,excellent physical and chemical stability,pH-triggered intestinal targeted slow-release properties,and potent antioxidant capacity.In vitro cell culture experiments showed that FC-ATX NPs promoted cellular uptake and scavenged excessive intracellular reactive oxygen species(ROS).In mouse models of colitis,FC-ATX NPs enhanced the drug absorption of intestinal epithelial cells and effectively accumulated at the site of inflammation.This work provides an efficient approach to enhance the bioavailability of ATX and has excellent application potential as an oral targeted delivery system for colitis therapy.