Size-Dependent Translocation of Nanoemulsions via Oral Delivery

Abstract

The in vivo translocation of nanoemulsions (NEs) was tracked by imaging tools with an emphasis on the size effect. To guarantee the accurate identification of NEs in vivo, water-quenching environment-responsive near-infrared fluorescent probes were used to label NEs. Imaging evidence confirmed prominent digestion in the gastrointestinal tract and oral absorption of integral NEs that survive digestion by enteric epithelia in a size-dependent way. In general, reducing particle size leads to slowed in vitro lipolysis and in vivo digestion, a prolonged lifetime in the small intestine, increased enteric epithelial uptake, and enhanced transportation to various organs. Histological examination revealed a pervasive distribution of smaller NEs (80 nm) into enterocytes and basolateral tissues, whereas bigger ones (550, 1000 nm) primarily adhered to villi surfaces. Following epithelial uptake, NEs are transported through the lymphatics with a fraction of approximately 3-6%, suggesting a considerable contribution of the lymphatic pathway to overall absorption. The majority of absorbed NEs were found 1 h post administration in the livers and lungs. A similar size dependency of cellular uptake and transmonolayer transport was confirmed in Caco-2 cell lines as well. In conclusion, the size-dependent translocation of integral NEs was confirmed with an absolute bioavailability of at least 6%, envisioning potential applications in oral delivery of labile entities.

Oral ionic liquid for the treatment of diet-induced obesity

“…The microscopic size of the aggregates was evident from DLS as well as the milky appearance of the emulsion. Xia et al (28) demonstrated that smaller nanoemulsions (∼100 nm) distribute to enterocytes and basolateral tissues and larger nanoemulsions (∼1,000 nm) adhered to villi. Larger particles were also shown to exhibit 2-fold lower bioavailability than smaller particles.…”

Oral Bioavailability and Lymphatic Transport of Pueraria Flavone-Loaded Self-Emulsifying Drug-Delivery Systems Containing Sodium Taurocholate in Rats

“…The area under the plasma concentration-time curve (AUC 0→ 8 ) of PFs-SMEDDS NR was remarkably higher than that of the PFs-suspension. The relatively enhanced bioavailability of PFs-SMEDDS NR may be attributed to the enhanced drug absorption by improving the solubility and membrane permeability of the poorly soluble drugs in the gastrointestinal tract [ 32 , 33 ]. After oral administration, SMEDDS spontaneously form tiny emulsion droplets with a diameter of ˂100 nm under physiological temperature and gastrointestinal peristalsis.…”

In situ monitoring of the structural change of microemulsions in simulated gastrointestinal conditions by SAXS and FRET

“…Hence, far more work should be carried out to resolve those questions. Apart from FRET and SAXS, other techniques have been used or might be used to study the fate of nanoparticles in the GI tract, such as cryo-TEM, near-infrared fluorescent dye, the water-quenching environment-responsive fluorescent probes, quantum dot and aggregation-induced emission (AIE) 18 , 31 ( Fig. 10 ).…”

“…Microemulsions coated with a dense PEG shell significantly avoid the hindrance of mucus, and several mucus-penetrating microemulsions have been reported 27 , 28 , 29 . Moreover, some reports demonstrated that partially intact lipid-based nanoparticles diffuse through the mucus layer, including the intestinal epithelium 30 , 31 . However, it worth noting that the intermediate phases will be inevitably affected by the mucus layer when passing through mucus, and the performance should be dependent on their physicochemical properties.…”