Nanocarriers: A General Strategy for Enhancement of Oral Bioavailability of Poorly Absorbed or Pre-Systemically Metabolized Drugs

Abstract

Oral delivery remains the preferred route for chronic drug administration thanks to its patient convenience and compliance. However, many drug candidates are unsuitable for conventional oral formulations due to low solubility, poor membrane permeability, or extensive pre-systemic metabolism. This review describes a promising strategy that incorporates or encapsulates the molecules with biodegradable and biocompatible nanoparticulate carriers. The entrapped drug substances can be protected against degradation by gastrointestinal fluids, while drug absorption through the gastrointestinal epithelium or lymphatic transport can be enhanced. Possible mechanisms for transport of these nanocarriers across gastrointestinal mucosa are introduced that focus on effects of size and surface properties of the nanocarriers on the non-specific or targeted uptake by enterocytes and/or M cells. Applications of various oral nanocarrier formulations, such as lipid nanoparticles, nanoemulsions and chitosan nanoparticles, are reviewed. Nanoparticulate drug carriers show great potential for improving the bioavailability of orally administered drugs.

Liver-targeting self-assembled hyaluronic acid-glycyrrhetinic acid micelles enhance hepato-protective effect of silybin after oral administration

“…It has been well accepted that particle size is a critical parameter to be controlled, in that it might play a key role in determining the fate of nanocarriers after oral administration (Cai et al, 2010 (DLS) measurement revealed that the mean particle size of two silybin-loaded micelles was around 130 nm and the size distribution was in the range of 60.3-269.7 nm. Therefore, silybin-loaded micelles might be transported in the small intestine by multiple pathways including endocytosis by enterocytes and M cells.…”

A study on enhanced intestinal permeability of clarithromycin nanoparticles

“…Several approaches have been applied in order to improve the oral bioavailability of poorly permeable and soluble compounds intended for oral administration. Using nanoparticulate drug delivery system is considered as one of these strategies (Cai et al, 2010;Saha et al, 2010). These formulations have been shown to be efficient approaches to enhance the transport of a large number of drugs including nucleic acids and genes across many biological membranes as well as to improve the stability of these materials.…”

Natural carriers for application in tuberculosis treatment

“…One of the reasons pointed as the basis of this decision is the fact that nanoparticle uptake by intestinal cells has been reported several times, either by the M-cells located in the Peyer's patches (Borges et al, 2006, Pinto Reis et , 2006) or by the enterocytes, benefiting from transcellular and paracellular transport (Cai et al, 2010, Pinto Reis et al, 2006. A first study revealed that, after oral delivery to mice of alginate nanoparticles containing the three drugs mentioned above plus etambutol, plasma drug levels were detected during 7-13 days.…”