Interspecies Uptake of Polymeric Microspheres

Nanomedicine for increasing the oral bioavailability of cancer treatments

Abstract

Oral administration is an appealing route of delivering cancer treatments. However, the gastrointestinal tract is characterized by specific and efficient physical, chemical, and biological barriers that decrease the bioavailability of medications, including chemotherapeutics. In recent decades, the fields of material science and nanomedicine have generated several delivery platforms with high potential for overcoming multiple barriers associated to oral administration. This review describes the properties of several nanodelivery systems that improve the bioavailability of orally administered therapeutics, highlighting their advantages and disadvantages in generating successful anticancer oral nanomedicines.

Graphical Abstract

Issues in Oral Nanoparticle Drug Carrier Uptake and Targeting

Some of the broader issues relating to the exploration of the use of nanoparticulate drug carriers by the oral route to achieve absorption of molecules which are poorly absorbed from the gastrointestinal tract are considered briefly here. These relate to both the pharmaceutical and biological characteristics of the carrier and carrier-gut interactions, the dynamic nature of such interactions, the varied modes of uptake, and the difficulties in targeting to the gut epithelium to encourage more efficient uptake of nanoparticles. These have the unhelpful habit of aggregating and flocculating hence increasing their effective size, when small size aids uptake and translocation. Post-absorption events can be equally hazardous and need further research. The question is asked whether or not it is wise load the gut lumen with molecules such as insulin even when protected in a carrier, and the suggestion is made that targets need to be rethought. The epithelium of the gut and the lymphoid tissue itself offers much scope for therapeutic interventions through nanoparticle delivery.

Nanoparticle uptake by the oral route: Fulfilling its potential?

The absorption of nanoparticles from the gastrointestinal tract is discussed first from a recent historical perspective, emphasising the crucial parameters that influence uptake, such as particle diameter, the nature of the particle and any surface modification with ligands designed to interact with receptors to facilitate targeting to and uptake into cells. Post-absorptive events, including translocation processes, are suggested here to be as important as initial uptake into the epithelial cells or M-cells of the gut associated lymphoid tissue.: