Pathways in the synthesis of functionalized glycolipids for liposomal preparations

We describe in this paper the synthesis of two glycolipids containing a mannosyl residue functionalized with malonic acid and azide groups at the C6 position. Two synthetic routes have been successfully implemented: the first one involves Schmidt's glycosylation procedure using functionalized carbohydrates, whereas the second one involves nucleophilic substitutions in the C6 position of an iodinated intermediate obtained using Koenigs-Knorr reaction. A comparative discussion of reactions and yields is realized. The two glycolipids served as material for the preparation of liposomes.

Self-organizing behaviour of glycosteroidal bolaphiles: insights into lipidic microsegregation

In this article we describe work on the synthesis of bolaphile biomimics composed of glucose head groups and steroidal units linked together by a methylene chain of varying length. The condensed phases formed by self-organization of the products as a function of temperature were characterized by differential scanning calorimetry and thermal polarized light microscopy. The results of these studies show that the thermal stabilities of the lamellar mesophases formed vary linearly as a function of increasing aliphatic composition, which reflects a linear hydrophobic-hydrophilic balance with respect to transition temperatures.

Gold nanoparticles decorated with mannose-6-phosphate analogues

Herein, the preparation of neoglycoconjugates bearing mannose-6-phosphate analogues is described by: (a) synthesis of a cyclic sulfate precursor to access the carbohydrate head-group by nucleophilic displacement with an appropriate nucleophile; (b) introduction of spacers on the mannose-6-phosphate analogues via Huisgen's cycloaddition, the Julia reaction, or the thiol-ene reaction under ultrasound activation. With the resulting compounds in hand, gold nanoparticles could be functionalized with various carbohydrate derivatives (glycoconjugates) and then tested for angiogenic activity. It was observed that the length and flexibility of the spacer separating the sugar analogue from the nanoparticle have little influence on the biological response. One particular nanoparticle system substantially inhibits blood vessel growth in contrast to activation by the corresponding monomeric glycoconjugate, thereby demonstrating the importance of multivalency in angiogenic activity.

Local Anaesthetic Activity in Diethylaminoacetyl Derivatives of Substituted Benzylamines

Six diethylaminoacetyl derivatives of general formula (III) are more potent than lignocaine as local anaesthetics. All cause erythema or necrosis of guinea-pig skin on intradermal injection except III, R = NH2, R' = H, and R = O(CH2)2Ph. This compound is several times more potent than lignocaine and in equipotent concentrations did not cause any tissue damage to skin on intradermal injection.

Synthesis and properties of isocannabinoid and cholesterol derivatized rhamnosurfactants: application to liposomal targeting of keratinocytes and skin

The usefulness of vesicles to cargo material depends on the design of new ligands able to incorporate easily inside the bilayer and also to direct the vesicles to the targeted site. Therefore, the synthesis of two new rhamnose-bearing surfactants is described. The hydrophobic part consists of cholesterol (in compound 3) and citrylidene phloroglucinol (in compound 6). The ability of these two rhamnolipids to incorporate into a DPPC membrane and to form aggregates is investigated, respectively, by differential scanning calorimetry and by surface tension measurements. Those two new surfactants were incorporated in fluorescent liposomes to study their interactions with keratinocytes and skin sections. Intraliposomal delivery to keratinocytes was observed in both cases, even if the kinetics of delivery were different according to the rhamnosurfactant used. Skin sections were stained by both liposomal formulations, and different interactions between the liposomes and skin cells according to the surfactant used were noted.