1,721,004 research outputs found
Unlocking new dimensions in long-acting injectables using lipid mesophase-based beads.
Full text linkIn this study, we explored the use of lipid mesophases (LMPs) as a biocompatible and biodegradable material for sustained drug delivery. Our hypothesis centered on leveraging the high surface-to-volume ratio of LMP-based beads to enhance strength, stability, and surface interaction compared to the LMP bulk gel. To modulate drug release, we introduced antioxidant vitamin E into the beads, influencing mesophase topologies and controlling drug diffusion coefficients. Four drugs with distinct chemical properties and intended for three different pathologies and administration routes were successfully loaded into the beads with a drug entrapment efficiency exceeding 80 %. Notably, our findings revealed sustained drug release, irrespective of the drugs' chemical properties, culminating in the development of an injectable formulation. This formulation allows direct administration into the target site, minimizing systemic exposure, and thereby mitigating adverse effects. Our approach demonstrates the potential of LMP-based beads for tailored drug delivery systems with broad applications in diverse therapeutic scenarios
Achiral dye/surfactant heteroaggregates for chiral sensing of phosphocholines
Full text linkAn investigation, based on absorption and circular dichroism spectroscopy, was carried out on assemblies formed in water upon the interaction of heteroaggregates, composed of dyes (Congo Red or Evans Blue) and cetyltrimethylammonium bromide (CTAB), with four enantiopure phopshocholines (DMPC, DPPC, DOPC, and POPC) characterized by the same po- lar head and different hydrophobic tails. The results show that the nature of the lipid as well as the concentration ratios influence sensitively the absorption and chiroptical properties of the su- pramolecular structure. Intriguingly, the transfer of chirality from the lipid to the assembly may be triggered or not, depending on the nature of the lipid hydrophobic chain. These findings con- firm the fundamental role of hydrophobic interactions in the transcription of chirality from mol- ecules to complex architectures
Molecular Packing in Langmuir Monolayers Composed of a Phosphatidylcholine and a Pyrene Lipid
No full textEnantiodiscrimination of bilirubin-IX alpha enantiomers in biomembrane models: Has chirality a role in bilirubin toxicity?
No full textSimple biomembrane models, namely micellar aggregates formed by enantiopure sodium N-acylprolinates, are able to convert the racemic mixture of bilirubin-IXα into an enantiomerically enriched mixture, thus suggesting a possible role of chirality in bilirubin toxicity due to the perturbation of neuron membrane dynamics. The length of alkyl chain does not influence the extent of equilibrium displacement, however, it affects the conformation of bilirubin, thus confirming the role of lipid structure in the membrane/bilirubin interaction, and suggesting a non-superficial main site of association. © 2008 Elsevier Inc. All rights reserved
Structurally Related Liposomes Containing N-Oxide Surfactants: Physicochemical Properties and Evaluation of Antimicrobial Activity in Combination with Therapeutically Available Antibiotics
Full text linkAlthough liposomes are largely investigated as drug delivery systems, they can also exert a pharmacological activity if devoid of an active principle as a function of their composition. Specifically, charged liposomes can electrostatically interact with bacterial cells and, in some cases, induce bacterial cell death. Moreover, they also show a high affinity toward bacterial biofilms. We investigated the physicochemical and antimicrobial properties of liposomes formulated with a natural phospholipid and four synthetic L-prolinol-derived surfactants at 9/1 and 8/2 molar ratios. The synthetic components differ in the nature of the polar headgroup (quaternary ammonium salt or N-oxide) and/or the length of the alkyl chain (14 or 16 methylenes). These differences allowed us to investigate the effect of the molecular structure of liposome components on the properties of the aggregates and their ability to interact with bacterial cells. The antimicrobial properties of the different formulations were assessed against Gram-negative and Gram-positive bacteria and fungi. Drug-drug interactions with four classes of available clinical antibiotics were evaluated against Staphylococcus spp. The target of each class of antibiotics plays a pivotal role in exerting a synergistic effect. Our results highlight that the liposomal formulations with an N-oxide moiety are required for the antibacterial activity against Gram-positive bacteria. In particular, we observed a synergism between oxacillin and liposomes containing 20 molar percentage of N-oxide surfactants on Staphylococcus haemolyticus, Staphylococcus epidermidis, and Staphylococcus aureus. In the case of liposomes containing 20 molar percentage of the N-oxide surfactant with 14 carbon atoms in the alkyl chain for S. epidermidis, the minimum inhibitory concentration was 0.125 mu g/mL, well below the breakpoint value of the antibiotic
Glucosylated pH-sensitive liposomes as potential drug delivery systems
No full textThe inclusion of pH-sensitive components in liposome formulations can allow a more controlled and efficient release in response to low pH typical of some pathological tissues and/or subcellular compartments. On the other hand decorating the surface of liposomes with sugar moieties attributes to lipid vesicles specificity toward lectins, sugar-binding proteins overexpressed in many tumor tissues. A novel multifunctional pH-sensitive glucosylated amphiphile was synthesized and characterized as pure aggregate component and in mixtures with a natural phospholipid. The comparison of the properties of the new glucosylated amphiphile with respect to those of a previously described cationic structural analogue demonstrates that the pH-sensitivity can strongly affect drug release, lipid organization, as well as the exposure of the glucose residues on liposome surface and their ability to interact with Concanavalin A, a plant lectin used as model system
Synthesis and Physicochemical Characterization of New Twin-Tailed N-Oxide Based Gemini Surfactants
No full textNew gemini surfactants (GSs) constituted by two double alkyl chain (from 7 to 17 methylenic units) N-oxide
monovalent surfactants joined by a PEG spacer of different length (from 3 to 21 ethylene glycol units), thus combining
the properties of both N-oxide and GS surfactants, were synthetized and characterized. The different hydrophilic/
hydrophobic balance of the molecular structure strongly influences the morphology and the electrical features of the
aggregates. Despite the zwitterionic nature of the polar head groups, all the aggregates are characterized by positive
potential thus suggesting protonation at the interface; however, the extent of protonation was shown to strongly depend
on the length of the alkyl chain and of the space
Carbazole Framework as Functional Scaffold for the Design of Synthetic Receptorsvia Ion Pair Asymmetric Nano-Organocatalysis
No full textCarbazole-based receptors play a crucial role in supramolecular chemistry, due to their unique geometry, photophysical properties, strong hydrogen bonding features, and versatility. This review examines prominent examples, focusing on how structural modifications shape binding affinity and selectivity for various guests, showcasing the potential of carbazole scaffolds to underpin innovation in synthetic receptor design
Synthesis and Physicochemical Characterization of New Twin-Tailed N-Oxide Based Gemini Surfactants
No full textNew gemini surfactants (GSs) constituted by two double alkyl chain (from 7 to 17 methylenic units) N-oxide monovalent surfactants joined by a PEG spacer of different length (from 3 to 21 ethylene glycol units), thus combining the properties of both N-oxide and GS surfactants, were synthetized and characterized. The different hydrophilic/hydrophobic balance of the molecular structure strongly influences the morphology and the electrical features of the aggregates. Despite the zwitterionic nature of the polar head groups, all the aggregates are characterized by positive potential thus suggesting protonation at the interface; however, the extent of protonation was shown to strongly depend on the length of the alkyl chain and of the spacer
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