Ethylcellulose nanoparticles as a new "in vitro" transfection tool for antisense oligonucleotide delivery.

Oil-in-water nano-emulsions have been obtained in the HEPES 20 mM buffer solution / [Alkylamidoammonium:Kolliphor EL = 1:1] / [6 wt% ethylcellulose in ethyl acetate] system over a wide oil-to-surfactant range and above 35 wt% aqueous component at 25 °C. The nano-emulsion with an oil-to-surfactant ratio of 70/30 and 95 wt% aqueous component was used for nanoparticles preparation. These nanoparticles (mean diameter around 90 nm and zeta potential of +22 mV) were non-toxic to HeLa cells up to a concentration of 3 mM of cationic species. Successful complexation with an antisense phosphorothioate oligonucleotide targeting Renilla luciferase mRNA was achieved at cationic/anionic charge ratios above 16, as confirmed by zeta potential measurements and an electrophoretic mobility shift assay, provided that no Fetal Bovine Serum is present in the cell culture medium. Importantly, Renilla luciferase gene inhibition shows an optimum efficiency (40%) for the cationic/anionic ratio 28, which makes these complexes promising for "in vitro" cell transfection.

Modulating size and surface charge of ethylcellulose nanoparticles through the use of cationic nano-emulsion templates.

Ethylcellulose nano-emulsions have been obtained by the low-energy phase inversion composition method in the Water / [Alkylamidoammonium: Cremophor WO7] / [6% ethylcellulose in ethyl acetate] system at 25 °C. It is shown that nano-emlulsions' composition variables (oil-to-surfactant ratio, cationic: nonionic surfactant ratio and polymer and water content) produce changes in their droplet diameter, surface charge and colloidal stability following defined trends. Nano-emulsions with good stability, droplet diameters between about 120 and 200 nm and surface charge from about 10 to 50 mV have been obtained. Nano-emulsions are further used as templates for nanoparticle dispersions preparation, which show sizes and surface charges typically smaller and similar respectively to their nano-emulsion templates. Cationic: nonionic surfactant ratio has the highest influence on both, size and surface charge, followed by oil-to-surfactant ratio and water content. Interestingly, the positive charge of the nanoparticles can be depleted under diluting conditions in a time-dependent manner.

Low-energy nano-emulsification approach as a simple strategy to prepare positively charged ethylcellulose nanoparticles.

Positively charged ethylcelulose nanoparticles have been obtained from alkylamidoammonium/Span 80 based nano-emulsion templates. Oil-in-water polymeric nano-emulsions form in a broad range of oil-to-surfactant ratios and water contents above 75 wt% by a low-energy method at 25 °C. Nano-emulsions with a water content of 90 wt% showed droplet sizes typically below 300 nm and high positive zeta potential values (∼55 mV). If oleylamine is added to the system, smaller droplet sizes and higher zeta potential values (∼66 mV) are obtained, but the stability of the nano-emulsions decreases. Although these nano-emulsions are destabilized by creaming, the period of stability is large enough to allow nanoparticle preparation by solvent evaporation. Polymeric nanoparticles obtained show a globular core-shell-like morphology, with mean diameters of around 250 nm. The surface charge of the nanoparticles is similar to that of the nano-emulsion template and remains positive after 24 h dialysis, suggesting slow desorption kinetics of the alkylamidoammonium from the nanoparticle surface. These results indicate that the proposed nano-emulsion approach is a good strategy for the preparation of positively charged nanoparticles from nonionic ethylcellulose polymers.

Hyaluronan based materials with catanionic sugar-derived surfactants as drug delivery systems.

In the present work novel drug delivery systems consisting in highly porous Hyaluronan foams for the administration of a non-steroidal anti-inflammatory drug (NSAID), ketoprofen, have been obtained. A sugar-derived surfactant associated with ketoprofen was prepared and incorporated into the porous hyaluronan materials. The association between a lactose derived surfactant, Lhyd12, and ketoprofen was obtained by acid-base reaction and its physicochemical properties were studied. Tensiometric and dynamic light scattering (DLS) determinations showed the formation of catanionic surfactant aggregates, Lhyd12/ketoprofen, in aqueous solution. Furthermore, the catanionic surfactants allowed greater solubilisation of ketoprofen. Hyaluronan porous materials were developed using butanediol diglycidyl ether as crosslinking agent. The profile release of Lhyd12/ketoprofen from hyaluronan based materials shows differences as a function of the aggregation state of catanionic surfactant.

PLGA nanoparticles from nano-emulsion templating as imaging agents: Versatile technology to obtain nanoparticles loaded with fluorescent dyes.

The interest in polymeric nanoparticles as imaging systems for biomedical applications has increased notably in the last decades. In this work, PLGA nanoparticles, prepared from nano-emulsion templating, have been used to prepare novel fluorescent imaging agents. Two model fluorescent dyes were chosen and dissolved in the oil phase of the nano-emulsions together with PLGA. Nano-emulsions were prepared by the phase inversion composition (PIC) low-energy method. Fluorescent dye-loaded nanoparticles were obtained by solvent evaporation of nano-emulsion templates. PLGA nanoparticles loaded with the fluorescent dyes showed hydrodynamic radii lower than 40nm; markedly lower than those reported in previous studies. The small nanoparticle size was attributed to the nano-emulsification strategy used. PLGA nanoparticles showed negative surface charge and enough stability to be used for biomedical imaging purposes. Encapsulation efficiencies were higher than 99%, which was also attributed to the nano-emulsification approach as well as to the low solubility of the dyes in the aqueous component. Release kinetics of both fluorescent dyes from the nanoparticle dispersions was pH-independent and sustained. These results indicate that the dyes could remain encapsulated enough time to reach any organ and that the decrease of the pH produced during cell internalization by the endocytic route would not affect their release. Therefore, it can be assumed that these nanoparticles are appropriate as systemic imaging agents. In addition, in vitro toxicity tests showed that nanoparticles are non-cytotoxic. Consequently, it can be concluded that the preparation of PLGA nanoparticles from nano-emulsion templating represents a very versatile technology that enables obtaining biocompatible, biodegradable and safe imaging agents suitable for biomedical purposes.

Studies on the formation of polymeric nano-emulsions obtained via low-energy emulsification and their use as templates for drug delivery nanoparticle dispersions.

Ethylcellulose nanoparticles have been obtained from O/W nano-emulsions of the water/polyoxyethylene 10 oleyl ether/[ethyl acetate+4wt% ethylcellulose] system by low energy-energy emulsification at 25°C. Nano-emulsions with droplet sizes below 200nm and high kinetic stability were chosen for solubilising dexamethasone (DXM). Phase behaviour, conductivity and optical analysis studies of the system have evidenced for the first time that both, the polymer and the drug play a role on the structure of the aggregates formed along the emulsification path. Nano-emulsion formation may take place by both, phase inversion and self-emulsification. Spherical polymeric nanoparticles containing surfactant, showing sizes below 160nm have been obtained from the nano-emulsions by organic solvent evaporation. DXM loading in the nanoparticles was high (>90%). The release kinetics of nanoparticle dispersions with similar particle size and encapsulated DXM but different polymer to surfactant ratio were studied and compared to an aqueous DXM solution. Drug release from the nanoparticle dispersions was slower than from the aqueous solution. While the DXM solution showed a Fickian release pattern, the release behaviour from the nanoparticle dispersions was faster than that expected from a pure Fickian release. A coupled diffusion/relaxation model fitted the results very well, suggesting that polymer chains undergo conformational changes enhancing drug release. The contribution of diffusion and relaxation to drug transport in the nanoparticle dispersions depended on their composition and release time. Surfactant micelles present in the nanoparticle dispersion may exert a mild reservoir effect. The small particle size and the prolonged DXM release provided by the ethylcellulose nanoparticle dispersions make them suitable vehicles for controlled drug delivery applications.

Galantamine-loaded PLGA nanoparticles, from nano-emulsion templating, as novel advanced drug delivery systems to treat neurodegenerative diseases.

Polymeric nanoparticles could be promising drug delivery systems to treat neurodegenerative diseases. Among the various methods of nanoparticle preparation, nano-emulsion templating was used in the present study to prepare galantamine-loaded nano-emulsions by a low-energy emulsification method followed by solvent evaporation to obtain galantamine-loaded polymeric nanoparticles. This approach was found to be suitable because biocompatible, biodegradable and safe nanoparticles with appropriate features (hydrodynamic radii around 20 nm, negative surface charge and stability higher than 3 months) for their intravenous administration were obtained. Encapsulation efficiencies higher than 90 wt% were obtained with a sustained drug release profile as compared to that from aqueous and micellar solutions. The enzymatic activity of the drug was maintained at 80% after its encapsulation into nanoparticles that were non-cytotoxic at the required therapeutic concentration. Therefore, novel galantamine-loaded polymeric nanoparticles have been designed for the first time using the nano-emulsification approach and showed the appropriate features to become advanced drug delivery systems to treat neurodegenerative diseases.

PLGA nanoparticles prepared by nano-emulsion templating using low-energy methods as efficient nanocarriers for drug delivery across the blood-brain barrier.

Neurodegenerative diseases have an increased prevalence and incidence nowadays, mainly due to aging of the population. In addition, current treatments lack efficacy, mostly due to the presence of the blood-brain barrier (BBB) that limits the penetration of the drugs to the central nervous system. Therefore, novel drug delivery systems are required. Polymeric nanoparticles have been reported to be appropriate for this purpose. Specifically, the use of poly-(lactic-co-glycolic acid) (PLGA) seems to be advantageous due to its biocompatibility and biodegradability that ensure safe therapies. In this work, a novel approximation to develop loperamide-loaded nanoparticles is presented: their preparation by nano-emulsion templating using a low-energy method (the phase inversion composition, PIC, method). This nano-emulsification approach is a simple and very versatile technology, which allows a precise size control and it can be performed at mild process conditions. Drug-loaded PLGA nanoparticles were obtained using safe components by solvent evaporation of template nano-emulsions. Characterization of PLGA nanoparticles was performed, together with the study of the BBB crossing. The in vivo results of measuring the analgesic effect using the hot-plate test evidenced that the designed PLGA loperamide-loaded nanoparticles are able to efficiently cross the BBB, with high crossing efficiencies when their surface is functionalized with an active targeting moiety (a monoclonal antibody against the transferrin receptor). These results, together with the nanoparticle characterization performed here are expected to provide sufficient evidences to end up to clinical trials in the near future.

Multifunctional polyurethane-urea nanoparticles to target and arrest inflamed vascular environment: a potential tool for cancer therapy and diagnosis.

Activation of inflammatory pathways in endothelial cells contributes to tumour growth and progression in multiple human cancers. Cellular adhesion molecules are involved in leukocyte recruitment to the vascular inflammatory environment where it plays a critical role in angiogenesis, suppression of apoptosis, proliferation, invasion and metastasis. We describe here the development of streptavidin-coated polyurethane-urea nanoparticles as multifunctional nanocarriers for fluorescence imaging or targeting of the tumour environment to identify and arrest the vascular network irrigating the tumour tissue. The design of these multifunctional nanoparticles involves incorporating streptavidin to the nanoparticle polymeric matrix. The obtained nanoparticles are spherical and exhibit an average diameter of 70-74 nm. Streptavidin-coated nanoparticles spontaneously bind biotinylated antibodies against VCAM-1 and ICAM-1 which in vitro and in vivo specifically attached to inflamed endothelial cells. Indeed the incorporation of CBO-P11 (a specific inhibitor of the vascular endothelial growth factor proangiogenic and proinflammatory pathway) to these nanoparticles allows a targeted pharmacological effect thereby decreasing the proliferation only in inflamed endothelial cells. The multiple functionalisation strategy described here could be exploited for tumour diagnostics or targeted drug delivery to tumour vasculature with a good safety profile and an attractive array of possibilities for biomedical applications.

Aplicación de los contenidos formativos de un Máster en Docencia Universitaria a la elaboración del plan docente de una asignatura adaptada al EEES / Application of the contents of a Master on Teaching in Higher Education to the planning of a subject adapted to EHEA

La formación y profesionalización de las tareas docentes es una de las respuestas a las exigencias decalidad y excelencia docentes. Ser un profesional docente eficiente y eficaz requiere la adquisición deunas competencias que permitan ejercer su función adecuadamente. La planificación de una nuevaasignatura en el marco del Espacio Europeo de Educación Superior (EEES) supone un reto que hayque asumir para realizar una docencia de calidad. La puesta en marcha de una nueva asignatura es unagran oportunidad para reflexionar individualmente y con otros profesores sobre la práctica docente ypara profundizar en procesos de innovación en metodología docente, en los recursos a utilizar, en lossistemas de evaluación, en la definición de objetivos y en la selección de contenidos.El objetivo del trabajo realizado consistió en aplicar los conocimientos adquiridos en el Máster en“Docencia Universitaria para profesorado novel” a la elaboración del plan docente de la asignatura“Farmacia Galénica I” que se impartirá en el sexto semestre del Grado de Farmacia en la Universidadde Barcelona. El plan docente que se ha elaborado ha tenido como referente las competencias de latitulación y los contenidos se han delimitado en relación a los objetivos formativos de la asignatura.Las estrategias metodológicas propuestas y la evaluación del proceso de aprendizaje se han adaptado ala docencia de grupos muy numerosos (80-100 alumnos), intentando favorecer la autonomía delalumnado(AU)

The training and professionalization of the educational tasks is one of the answers to the educationalrequirements of quality and excellence. To be an efficient and effective professional need theacquisition of a few competences that allows exercising his function adequately. The planning of anew subject in the frame of the European Higher Education Area (EHEA) supposes a challenge that itis necessary to take up to manage a high quality teaching. The development of a new subject is a greatopportunity to think individually and with other colleagues on the educational practice and to penetrateinto processes of innovation into educational methodology, in the higher education resources, in theevaluation, in the definition of aims and in the selection of contents.The aim of the present work consisted of applying the knowledge acquired in the Master in "HigherEducation Teaching for young teachers" to the elaboration of the learning plan of the subject"Farmacia Galénica I" that will be given in the sixth semester of the Degree of Pharmacy in theUniversity of Barcelona. The learning plan that has been elaborated has taken the competences of thedegree in Pharmacy as a model and the contents have been delimited in relation to the formative aimsof the subject. The methodological strategies and the evaluation of the learning process have beenadapted to the teaching of groups with 80-100 students, trying to help the autonomy of the student(AU)

A study on the influence of emulsion droplet size on the skin penetration of tetracaine.

OBJECTIVES/AIMS: The influence of emulsion droplet size on the skin penetration of a model drug, tetracaine, was studied. For this purpose, in vitro dermal and transdermal delivery of tetracaine from 6 emulsions (3 macro-emulsions with droplet sizes >1 microm and 3 nano-emulsions with droplet sizes <100 nm) were tested. METHODS: Two approaches were used: in the first one, the composition of the emulsions was kept constant, while in the second one, the surfactant concentration in the aqueous phase was kept constant by varying the overall surfactant concentration. RESULTS: The results from emulsions differing only in droplet size did not provide statistically significant evidence for the anticipated increase in transdermal or dermal delivery (after 24 h) when reducing emulsion droplet size. The same results were obtained when the surfactant concentration in the aqueous phase was kept constant, indicating that there is no influence of emulsion droplet size on the skin penetration of tetracaine within the droplet size range studied. CONCLUSION: This is in contrast to what has been reported in various publications that claim penetration to increase with reducing droplet size. It should be noted that the results reported so far are based on emulsions that apart from droplet size also differed in composition and/or system components.

Oil/water droplet formation by temperature change in the water/c(16)e(6)/mineral oil system.

Droplet sizes of oil/water (O/W) nanoemulsions prepared by the phase inversion temperature (PIT) method, in the water/C16E6/mineral oil system, have been compared with those given by a theoretical droplet model, which predicts a minimum droplet size. The results show that, when the phase inversion was started from either a single-phase microemulsion (D) or a two-phase W+D equilibrium, the resulting droplet sizes were close to those predicted by the model, whereas, when emulsification was started from W+D+O or from W+D+Lalpha (Lalpha = lamellar liquid crystal) equilibria, the difference between the measured and predicted values was much higher. The structural changes produced during the phase inversion process have been investigated by the 1H-PFGSE-NMR technique, monitoring the self-diffusion coefficients for each component as a function of temperature. The results have confirmed the transition from a bicontinuous D microemulsion at the hydrophile-lipophile balance (HLB) temperature to oil nanodroplet dispersion in water when it is cooled to lower temperatures.