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1,3:2,4-Dibenzylidene-D-sorbitol (DBS) and 12-hydroxystearic acid (12-HSA) are well-known as low-molecular-weight organogelators (LMOGs) capable of gelling an organic liquid phase. Considering their unique chemical and physical properties, we assessed their potential effects in new lipstick formulations by discrimination testing, in vitro measurements of the sun protection factor (SPF), and thermal, mechanical and texture analyzes. DBS and 12-HSA were used to formulate four types of lipsticks: L1 (1% DBS), L2 (10% 12-HSA), L3 (1.5% DBS) and L4 (control, no LMOGs). The lipsticks were tested for sensory perception with an untrained panel of 16 consumers. LMOG formulations exhibited higher UVA protection factor (UVA-PF) and in vitro SPF, particularly in the 12-HSA-based lipstick. Regarding thermal properties, the 12-HSA-based lipstick and those without LMOGs were more heat-amenable compared to thermoresistant DBS-based lipsticks. The results also showed the viscoelastic and thermally reversible properties of LMOGs and their effect of increasing pay-off values. In general, the texture analysis indicated that 12-HSA-based lipstick was significantly harder to bend compared to control, while the other formulations became softer and easier to bend throughout the stability study. This work suggests the potential use of LMOGs as a structuring agent for lipsticks, paving the way towards more photoprotective and sustainable alternatives.

Organogels are semi-solid systems with an organic liquid phase immobilized by a three-dimensional network composed of self-assembled, crosslinked or entangled gelator fibers. Organogel applications are various, including chemistry, pharmaceuticals, cosmetics, biotechnologies and food technology. In pharmacology, they are used as drug and vaccine delivery platforms for active ingredients via diverse routes such as transdermal, oral and parenteral. In a close past, their uses as drug delivery systems have been unfortunately hampered by the toxicity of the selected organic solvents. More recently, the synthesis of more biocompatible organogels has strengthened the development of several biomedical and pharmaceutical applications. This review provides a global view of organogels, such as nature, syntheses, characterizations and properties. An emphasis is placed on the most recent technologies used in the design of organogels as potential controlled delivery systems. A particular attention is provided to their newest therapeutic applications.

Organogels prepared with low molecular weight organogelators to structure liquid oils represent excellent matrices for the controlled delivery of a wide variety of drug molecules. Although studies on organogel systems are reported in the literature, relatively few investigate their potential as gels formed in situ intended for drug delivery. This study reports the development of injectable subcutaneous 12- hydroxystearic acid (12-HSA) organogels for the delivery of both lipophilic and hydrophilic drugs. The rheological characterization (flow, dynamic temperature ramp and amplitude oscillatory measurements) and physicochemical properties (syringeability, swelling and degradation studies), as well as permeability and cytotoxicity were analyzed to gain insights into the influence of the gel composition (surfactant addition, organogelator concentration) on the gelation process and organogel properties. Sol-gel phase transition temperature (Tgel) and gel-sol phase transition temperature (Tmelt) were determined by the tube-inverting method and complementary rheology studies. An increase in 12-HSA concentration led to an augmentation in gel strength and storage (G′) and loss (G″) moduli values, evidencing the self-assembly of crystalline gelator structure entrapping the oil phase into a three-dimensional (3D) network. The addition of polysorbate 80 (Tween 80, T80) surfactant molecules in the system caused a weaker gel-like structure, with lower flow rate during syringeability assays, despite its lower apparent viscosity compared to those of 12-HSA organogels. In addition, the swelling studies of 12-HSA/12-HSA T80 organogels as a function of time in phosphate buffered saline (PBS) revealed that the erosion rates were modulated by the organogel compositions. The permeability of acyclovir (ACV) and clotrimazole (CTM), hydrophilic and lipophilic model drugs, respectively, loaded in 12-HSA-based organogels, was assessed in Franz diffusion cells. Organogel-loaded drugs presented lower in vitro release rates and ex vivo drug permeabilities compared to the corresponding drug solutions. Furthermore, 12-HSA T80 organogel could slow down the release of ACV by a factor of about 2.6-fold, up to 6 h, compared to CTM-loaded 12-HSA organogels. Finally, the cytotoxicity of 12-HSA-based organogels was evaluated through in vitro cell viability assays in human foreskin fibroblasts (HFF). Increased 12-HSA concentration resulted in higher cytotoxic effect, with a higher test sensitivity observed for the 3D collagen-embedded cell layer setup matrix versus 2-D cell cultures. Our results support the hypothesis that 12-HSA-based organogels are promising systems for controlled drug delivery as in situ-forming implants.

Most bioactive food components show a rapid inactivation or biodegradation that challenge their beneficial effects. Since regulation authorities require efficient food quality and acceptability, edible passive coating has been developed to improve and extend food shelf life while protecting nutritional values. Encapsulation processes in oil and fat structures therefore provide a high protection for fat soluble nutraceuticals, as sustained and controlled delivery systems. Among the various existing systems, nanoorganogels offer unique properties due to their multiplied surface, while preserving the physical properties of bulk materials. Thus, nanoencapsulation currently receives a lot of attention from industrial R&Ds. Screening approaches have been developed to promote food-grade and GRAS-approved organogelators available for the scaled up manufacture of nanoscale organogel delivery systems. Ongoing challenges of the food industry include intensifying the search for viable health-promoting nanomaterials or nanostructured matrices displaying desirable properties in food applications. In these aspects, the nanoorganogel technologies have recently shown tremendous potential in food applications as structured edible oils, dietary supplements with high oral bioavailability or safer preservative agents for consumers.

The interest in using colloidal dispersions of gelled lipid nanoparticles (GLN) for different fields of application has increased in recent years, notably in cosmetic, dermatology, and/or pharmaceutics due to their capacity to immobilize compounds with poor water solubility. The pharmaceutical field desires to achieve lipophilic drug formulations which are able to conserve their stability, although it is well-known that emulsions and solid lipid nanoparticles (SLN) present a lack of stability over time, leading to system destabilization. Furthermore, stable colloidal dispersions of gelled oil particles do not affect the properties of the molecule to be delivered, and they result as an alternative for the previously appointed systems. This review is an attempt to present the reader with an overview of colloidal dispersions of GLN, their concept, formulation methods, as well as the techniques used for their characterization. Moreover, various application fields of organogel dispersions have been illustrated to demonstrate the potential application range of these recent materials.

The rheological properties of a new type of colloidal dispersion based on nanoparticles of gelled oil have been characterized. The nanoparticles (mean diameter approximately 250 nm) were viscoelastic droplets of dicaprylyl ether gelled by 12-hydroxystearic acid (HSA) and were stabilized in aqueous solutions by cetyltrimethylammonium bromide. The effects of the volume fraction of the dispersed organogel phase and of the organogelator concentration upon viscoelasticity of the dispersion were investigated and compared to the corresponding emulsion (without HSA). The shear viscosity of the dispersions of organogel droplets and the elastic and viscous moduli (G' and G'') were found to increase when the proportion of organogelator was increased. More surprisingly, the shear-thinning behavior was also more pronounced. The rheological behavior of the dispersions could be explained by strong interactions between some gelled particles. This hypothesis was supported by electron microscopy observations showing some particles bridged together by ribbons of HSA fibers.

Objectives The aims of the study were to determine the in vitro drug release of guar gum-coated capsules of ronidazole, and to evaluate the pharmacokinetics and efficacy of this formulation for the treatment of cats naturally infected with Tritrichomonas foetus. Methods The pharmacokinetics of ronidazole were evaluated in five healthy cats and five cats infected with T foetus. In a second step, the clinical efficacy of these capsules was evaluated by a controlled, randomised, double-blind clinical trial performed in 47 infected cats from French catteries. In this study, cats were randomly allocated to either the ronidazole treatment group (n = 25) or a placebo group (n = 22). Ronidazole (30 mg/kg) q24h for 14 days was administered to the treated cats. After 14 days of treatment, the presence of T foetus was tested by conventional PCR assay. Results In the pharmacokinetic study, a delayed peak plasma concentration was observed in healthy and infected cats, with no significant difference between these two groups (mean geometric mean of 9 h for time to maximum plasma concentration [Tmax], 21.6 µg/ml for time to maximum plasma concentration [Cmax] and 467.4 μg/h/ml for the area under the curve [AUC] in healthy cats; and 9.4 h for Tmax, 17.1 µg/ml for Cmax and 481 μg/h/ml for AUC in infected cats). In the clinical trial, T foetus was detected in 16% of cats from the treated group and 82% of cats from the placebo group at the end of the study ( P Conclusions and relevance Oral administration of guar gum-coated capsules of ronidazole at a dose of 30 mg/kg once daily for 14 days delays the peak plasma concentration and eradicates infection in most cases.

Es wurde ein neuartiges Ammoniak-Generator-Verfahren zur Ammoniakerzeugung an Bord von Diesel-PKW aus wässrigen Lösungen von Guanidinium Formiat (GuFo) und von Harnstoff (AdBlue) sowie aus ternären wässrigen Lösungen von GuFo und Harnstoff entwickelt. Schwerpunkt der Forschungsaktivitäten war die Entwicklung eines Generators zur Erzeugung von Ammoniak unter gegebenen reduktionsmittelspezifischen und motorischen Randbedingungen. A novel generator for the ammonia production ”on-board“ of Diesel engine powered vehicles from aqueous solutions of ammonia precursor compounds like Guanidinium Formate (GuFo), Urea (AdBlue) and ternary aqueous solutions of GuFo and Urea was developed. From the technical point of view the main outcome of the research project was a prototype suitable for typical small Diesel engine conditions tailored to the properties of the ammonia precursor.

Several excipients are commonly used to enhance the drug absorption through simple epithelia of the digestive tract. They permeate the paracellular barrier constituted by tight junctions (TJs). We compared the effects of two excipients, sodium caprate (C10) and a self-emulsifying excipient Labrasol composed of a mixture of caprylocaproyl polyoxyl-8 glycerides, both applied to emerged reconstructed human epidermis either 'systemically', that is by addition to the culture medium, or topically. During the 'systemic' application, which produced cytoplasmic translocation of occludin and leakage of the biotin marker into the lower stratum corneum, the decrease in the trans-epithelial electrical resistance (TEER) was less abrupt with Labrasol when compared with C10, even though both excipients produced comparable final effects over time. With topical Labrasol, a significant TEER decrease was obtained with 5 times the 'systemic' concentrations. Topical application of C10 also resulted in the loss of the barrier function measured with TEER but had dramatic deleterious effects on the tissue morphology observed with light and electron microscopy. Our study demonstrates the potential value of Labrasol as an enhancer of bioavailability of molecules applied through the transcutaneous route. Our results suggest modulation of the epidermal TJs by both compounds. Even though the C10 action was at least partly due to overall cell damage and despite the fact that the decrease in TEER after topical application was apparently related to the permeabilization of the primary barrier of the stratum corneum in the first place.

The synthesis of a number of new 2,2′-bipyridine ligands functionalized with bulky amino side groups is reported. Three homoleptic polypyridyl ruthenium (II) complexes, [Ru(L)3]2+ 2(PF6−), where L is 4,4′-dioctylaminomethyl-2,2′-bipyridine (Ru4a), 4,4′-didodecylaminomethyl-2,2′-bipyridine (Ru4b) and 4,4′-dioctadodecylaminomethyl-2,2′-bipyridine (Ru4c), have been synthesized. These compounds were characterized and their photophysical properties examined. The electronic spectra of three complexes show pyridyl π π* transitions in the UV region and metal-to-ligand charge transfer bands in the visible region. Copyright © 2005 John Wiley & Sons, Ltd.

The conversion of 1,ω-dialcohols (C 6 –C 16 ) to dihalides—dibromides and diiodides—was successfully obtained in the couple “PTSA/1-alkyl-3-methylimidazolium ionic liquids” (OMIM/X, BMIM/X; i -PMIM/X) for 2 h at 110 °C. The dihalogenation was improved by the use of microwaves irradiation. The “PTSA-ionic liquid”-couple was regenerated and reused. The kinetics of halogenation of fatty dialcohols confirmed the A2 (or SN2c) mechanism in which monohalogenation was four-fold faster than dihalogenation.

Formulation of dermatological medicines in hospitals is a multidisciplinary challenge addressing pharmaceutical issues such as (1) excipient availability and safety, (2) drug solubility and diffusivity, (3) drug-excipient compatibility, (4) formulation stability, and (5) convenience of use. Thermosensitive hydrogels are polymeric excipients that exhibit interesting properties, especially solubilizing properties and the ability to physically respond to thermal physiological stimuli. The inclusion of such polymers in dermatological formula enables to produce “intelligent medicines” that outgrow problems encountered with conventional formulations and to design novel delivery systems. This chapter will detail pharmaceutical considerations about excipient choice and thermosensitive polymers and illustrate the possibilities they offer by various formulation and clinical application examples.

The effect of mixed sulfur oxides pretreatment on the surface state and carbon monoxide oxidation activity of Cu x Zn 1− x Cr 2 O 4 mixed oxides, has been investigated using X-ray photoelectron spectroscopy (XPS) and kinetic measurements. The results obtained indicate that SO x species bind preferentially to the surface zinc ions, which thus protect from poisoning the surface copper ions which are the active species for carbon monoxide oxidation.

International audience; Based on the organogel concept, in which an oil is trapped in a network of low-molecular-mass organic gelator fibres creating a gel, a formulation of gelled soya bean oil nanoparticles was evaluated for its capacity to form biocompatible hydrophobic reservoirs. The aqueous dispersions of nanoparticles were prepared by hot emulsification (T° > Tgel) and cooling at room temperature in the presence of polyethyleneimine (PEI). The dispersions were stabilised by the electrostatic interactions between the positively charged amino groups of the PEI and the negatively charged carboxylates of the gelator fibres present at the surface of the particles. The aqueous dispersions were highly stable (several months) and the gelled particles were able to entrap a hydrophobic fluorescent model molecule (Nile red), allowing testing in cells. The gelled oil nanoparticles were found to be biocompatible with the tested cells (keratinocytes) and had the ability to become rapidly internalised. Thus, organogel-based nanoparticles are a promising hydrophobic drug delivery system.

В настоящата дисертация са изследвани възможностите за получаване на сорбционни слоеве от метални оксиди с оглед на тяхното приложение като сензорни елементи. Изследванията са насочени към детайлно охарактеризиране на структурата, морфологията, повърхностния състав и химичните свойства на отложени с различни методи, слоеве от TiO2, SnO2, MoO3 и ZnO. Получени са гладки слоеве от метални оксиди чрез rf магнетронно разпрашване и отлагане от течна фаза. Формирани са и наноструктури от TiO2, SnO2, MoO3 и ZnO чрез импулсно лазерно отлагане във въздух при атмосферно налягане, както и структури от ZnO чрез импулсно лазерно отлагане в кислородна атмосфера и използването на подложен слой от Au, AuAg и Ag. За охарактеризиране на слоевете е използвано съчетание на различни аналитични методи, като XPS, XRD, SEM и TEM. Изследвана е реакционната способност на получените чрез лазерно отлагане сензорни слоеве от TiO2, SnO2, MoO3 и ZnO при експозиция на различни газови молекули (CO, NH3, ацетон и етанол) при стайна температура. Изследвани са възможностите за подобряване на газочувствителните свойства на сензорните елементи, чрез дотиране с благородни метали (Pd и Au), създаване на нанокомпозити Pd-ZnO и Au-ZnO, и облъчване на повърхността с монохроматична светлина с различна дължина на вълната. Предложен е перспективен подход за формиране чрез импулсно лазерно отлагане на порьозни наноструктури от TiO2, MoO3 и SnО2 и ZnO метални оксиди с приложение като сензорни елементи за детекция на различ, In the present dissertation we studied different methods aiming the growth of reliable sorption metal-oxides thin films for sensor element application. Detailed characterization of the morphology and the chemical state of TiO2, SnO2, MoO3 and ZnO layers deposited by pulsed laser ablation (PLD) in air at atmospheric pressure were performed. The latter, (ZnOfilms) were grown onto annealed substrates of Au, Au, Ag and Ag which yield a nanoporous structures with high adsorption coefficient. Those structures were analyzed by XPS, XRD, SEM and AFM. The reactivity abilities of TiO2, SnO2, MoO3 and ZnO deposited by PLD were studied in room temperature. In order to raise the gas-sensibility, we adopted a dotting technique with noble metals, such as, Pd and Au, both leading to nanocomposites - Pd-ZnO and Au-ZnO. Moreover, irradiations with monochromatic light source with different wave length lead to further improvement of the sensing performance. The obtained sensors show relatively high sensing behavior towards ammonia acetone and ethanol.