Mass-suppressed effects in heavy quark diffusion

Many lattice studies of heavy quark diffusion originate from a colour-electric correlator, obtained as a leading term after an expansion in the inverse of the heavy-quark mass. In view of the fact that the charm quark is not particularly heavy, we consider subleading terms in the expansion. Working out correlators up to $O(1/M^2)$, we argue that the leading corrections are suppressed by $O(T/M)$, and one of them can be extracted from a colour-magnetic correlator. The corresponding transport coefficient is non-perturbative already at leading order in the weak-coupling expansion, and therefore requires a non-perturbative determination.Comment: 21 pages. v2: clarifications adde

Delivery of Peptides Via the Oral Route: Diabetes Treatment by Peptide-Loaded Nanoparticles.

Over the last years, the interest of the pharmaceutical industry in the use of therapeutic peptides in diabetes treatment has been increased. However, these are restricted to parenteral administration. In order to mimic the natural physiological response, many efforts have been made towards oral peptide delivery in diabetes treatment. This review article aims to give an overview on the progress in the nanomedicine field towards the design and optimization of nanoparticle-based drug delivery systems capable of overcoming the harsh gastrointestinal environment and achieving an adequate bioavailability following oral administration. The reported data clearly illustrate the promise of nanomedicine for antidiabetic oral peptide delivery

G om trie synth tique

SIGLEBSE B223828D / UCL - Université Catholique de LouvainBEBelgiu

The stimulation of GLP-1 secretion and delivery of GLP-1 agonists via nanostructured lipid carriers.

Nanoparticulate based drug delivery systems have been extensively studied to efficiently encapsulate and deliver peptides orally. However, most of the existing data mainly focus on the nanoparticles as a drug carrier, but the ability of nanoparticles having a biological effect has not been exploited. Herein, we hypothesize that nanostructured lipid carriers (NLCs) could activate the endogenous glucagon-like peptide-1 (GLP-1) secretion and also act as oral delivery systems for GLP-1 analogs (exenatide and liraglutide). NLCs effectively encapsulated the peptides, the majority of which were only released under the intestinal conditions. NLCs, with and without peptide encapsulation, showed effective induction of GLP-1 secretion in vitro from the enteroendocrinal L-cells (GLUTag). NLCs also showed a 2.9-fold increase in the permeability of exenatide across the intestinal cell monolayer. The intestinal administration of the exenatide and liraglutide loaded NLCs did not demonstrate any glucose lowering effect on normal mice. Further, ex vivo studies depicted that the NLCs mainly adhered to the mucus layer. In conclusion, this study demonstrates that NLCs need further optimization to overcome the mucosal barrier in the intestine; nonetheless, this study also presents a promising strategy to use a dual-action drug delivery nanosystem which synergizes its own biological effect and that of the encapsulated drug molecule