Liposomes for topical use: physico-chemical comparison of vesicles prepared from egg or soy lecithin

Developments in nanotechnology and in the formulation of liposomal systems provide the opportunity for cosmetic dermatology to design novel delivery systems. Determination of their physico-chemical parameters has importance when developing a nano-delivery system. The present study highlights some technological aspects/characteristics of liposomes formulated from egg or soy lecithins for topical use. Alterations in the pH, viscosity, surface tension, and microscopic/macroscopic appearance of these vesicular systems were investigated. The chemical composition of the two types of lecithin was checked by mass spectrometry. Caffeine, as a model molecule, was encapsulated into multilamellar vesicles prepared from the two types of lecithin: then zeta potential, membrane fluidity, and encapsulation efficiency were compared. According to our observations, samples prepared from the two lecithins altered the pH in opposite directions: egg lecithin increased it while soy lecithin decreased it with increased lipid concentration. Our EPR spectroscopic results showed that the binding of caffeine did not change the membrane fluidity in the temperature range of possible topical use (measured between 2 and 50 °C). Combining our results on encapsulation efficiency for caffeine (about 30% for both lecithins) with those on membrane fluidity data, we concluded that the interaction of caffeine with the liposomal membrane does not change the rotational motion of the lipid molecules close to the head group region. In conclusion, topical use of egg lecithin for liposomal formulations can be preferred if there are no differences in the physico-chemical properties due to the encapsulated drugs, because the physiological effects of egg lecithin vesicles on skin are significantly better than that of soy lecithin liposomes

Farm to table: Residues of different pesticides in tomato and tomato juice – Food safety aspects

During plant cultivation, the pesticides can get into the tissue of vegetables due to crop protection processes, and thus into the food chain. Therefore, they constitute a potential risk to the consumer's health. Depletion of pesticides [spirotetramat (Movento), azoxystrobin and difenoconazole (Amistar Top)] was monitored by testing tomatoes treated individually or simultaneously and tomato juices prepared from the treated tomatoes. The investigations aimed to reveal any kinetic interaction between the compounds tested and changes in their elimination, and thus to assess their compliance with the official Maximum Residue Limits (MRLs). The co-presence of pesticides prolonged the elimination of the individual compounds which reached significantly higher residue levels ( P < 0.0001) in tomato, especially difenoconazole (45%) and azoxystrobin (50%) on day 8 after treatment that can cause food safety issues to the human consumers. However, the concentrations of pesticides applied alone or simultaneously were found to be below the corresponding MRL values after the withdrawal period in all investigated tomato and tomato juice samples. Accordingly, the investigated pesticides can be safely used simultaneously, their concentrations are in compliance with the legal regulations and thus their concomitant presence does not pose any risk to the consumers' health

A sejtek közti kommunikáció újonnan azonosított mikrovezikulum-útjának vizsgálata = Analysis of cell-derived microvesicles that represent novel players in intercellular communication

Munkánk során az extracelluláris vezikulák izolálásának és detektálásának számos meghatározó preanalitikai és analitikai paraméterére hívtuk fel a figyelmet. Elsőként mutattunk rá, hogy a mikrovezikulák és a fehérje-aggregátumok biofizikai paraméterei jelentős mértékben átfednek, és ez zavarhatja a mikrovezikulák mérését. Kidolgoztuk annak módszerét, hogy egyazon biológiai forrásból származó különböző vezikula populációkat párhuzamosan, nagy mennyiségben, intakt formában tudjunk izolálni. Összehasonlító proteomikai elemzést végeztünk thymus eredetű apoptotikus testek és mikrovezikulák esetében. Számos T sejt jelátvitelben és immunfolyamatokban szerepet játszó fehérjét és autoantigént azonosítottunk. Igazoltuk, hogy T sejt eredetű citokinek és extracelluláris vezikulák együttes hatását monociták génexpressziójára. Igazoltuk, hogy a mikrovezikulák önálló ionháztartással rendelkeznek. Kimutattuk, hogy thymocyta exoszómák nem tartalmaznak riboszómális RNS-eket, azonban feldúsulnak bennük kis RNS-ek (pl. bizonyos miRNS-ek). Polymyositises betegekben emelkedett keringő mikrovezikula számot mutattunk ki, mely korrelált a betegség bizonyos klinikai paramétereivel. Végül elsőként igazoltuk, hogy egészséges T sejt eredetű mikrovezikulák CD62P-CD161 kölcsönhatás révén specifikusan kötődnek monociták felszínéhez. | In our work we drove attention to several pre-analytical and analytical parameters affecting isolation and detection of work extracellular vesicles. We were the first to describe that microvesicles share biophysical parameters with protein aggregates which may confound microvesicle assessment by flow cytometry. We developed protocols for the isolation of large amounts of intact vesicle types secreted simultaneously by the same biological source. We carried comparative proteomic analysis of murine thymus derived apoptotic bodies and microvesicles. We identified large number of proteins involved in T cell signaling or immune functions as well as autoantigens within these structures. We provided evidence fro crosstalk between T cell derived extracellular vesicles and cytokines on the gene expression of monocytes. We have shown that microvesicles possess autonomous ion homeostasis. We found that thymocyte derived exosomes lacked the 18S and 28S ribosomal RNA molecules, while they were enriched in small RNA species (e.g. certain miRNAs). We described that patients with polyomyelitis were characterized by elevated levels of circulating microvesicle. Monocyte- and B cell-derived microvesicle numbers correlated with certain clinical parameters of the diseases. Finally, for the first time we showed that HLA-G+, trophoblast-derived microvesicles isolated from healthy pregnant blood plasma samples, bound specifically to T cells via CD62P-CD161 interaction, and induced STAT3 phosphorylation

Inclusion complexation of the anticancer drug pomalidomide with cyclodextrins: fast dissolution and improved solubility

Pomalidomide (POM), a potent anticancer thalidomide analogue was characterized in terms of cyclodextrin complexation to improve its aqueous solubility and maintain its anti-angiogenic activity. The most promising cyclodextrin derivatives were selected by phase-solubility studies. From the investigated nine cyclodextrins – differing in cavity size, nature of substituents, degree of substitution and charge – the highest solubility increase was observed with sulfobutylether-β-cyclodextrin (SBE-β-CD). The inclusion complexation between POM and SBE-β-CD was further characterized with a wide variety of state-of-the-art analytical techniques, such as nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (IR), circular dichroism spectroscopy, fluorescence spectroscopy as well as X-ray powder diffraction method (XRD). Job plot titration by NMR and the AL-type phase-solubility diagram indicated 1:1 stoichiometry in a liquid state. Complementary analytical methods were employed for the determination of the stability constant of the complex; the advantages and disadvantages of the different approaches are also discussed. Inclusion complex formation was also assessed by molecular modelling study. Solid state complexation in a 1:1 M ratio was carried out by lyophilization and investigated by IR and XRD. The complex exhibited fast-dissolution with immediate release of POM, when compared to the pure drug at acidic and neutral pH. Kinetic analysis of POM release from lyophilized complex shows that Korsmeyer-Peppas and Weibull model described the best the dissolution kinetics. The cytotoxicity of the complex was tested against the LP-1 human myeloma cell line which revealed that supramolecular interactions did not significantly affect the anti-cancer activity of the drug. Overall, our results suggest that the inclusion complexation of POM with SBE-β-CD could be a promising approach for developing more effective POM formulations with increased solubility

Nanoencapsulated and microencapsulated enzymes in drug antidotal therapy

A catalytic bioscavenger for the therapeutic and prophylactic defense against recognized chemical threat agents has been a long-standing objective of civilian and military research. Among the toxic agents, organophosphate molecules and cyanide have been widely studied. In order to overcome the limitations of traditional antidotal therapies, isolated, purified, recombinant enzymes with bacterial origin possessing fast catalytic activity were used in in vitro and in vivo experiments. However, the fast degradation, excretion and adverse immunologic reaction against enzymes limit their in vivo use. Development of biodegradable, nontoxic carrier systems, microparticles, and nanoparticles—offering advantageous pharmacokinetic parameters was suggested. Present work deals with the perspectives of carrier systems, such as resealed and annealed erythrocytes and sterically stabilized liposomes. Dendritic polymers and polymer-conjugated enzymes, being in the focus of extensive research efforts nowadays, are also discussed