No description available.

Dendrimers are characterized as synthetic, spherical macromolecules with tree- like branched structures. Their well-controlled sizes (3 - 10 nm), ease of functionalization, high water solubility, well-defined chemical structure, and biocompatibility make these nanomaterials attractive for a wide spectrum of promising biomedical applications. Peptide dendrimers and polyamidoamine (PAMAM) dendrimers have been used to date as effective transdermal or topical drug delivery systems, with the latest in a much greater extent. The structural characteristics of the aforementioned molecules guided us to design a novel repeating unit for dendrimers (monomer) possessing amino branching point and able to afford generation expanding through repeating amide bonds. The novel monomer, after appropriate modifications, was used to develop lower generations of polyamidoamino dendritic structures having amide groups and amino-branching points in their interior. The new dendrimers were isolated and fully characterized by typical spectroscopic technics. The final molecules will be used in human skin permeation experiments and will be evaluated for their effect on skin permeability.

Effect of the concentration of amino-decorated polyamidoamine dendrimers with ethylenediamine core at the (trans)dermal delivery of 5-Fluorouracil Pavlína Chladová Dendrimers are synthetic, symmetrically tree-like branched molecules. They are composed of repeating units (monomers). They have high density of surface functional groups and spherical shape in solution. Since their molecular weight is highly controllable, they are characterized by monodispersity and this is their main difference from classical polymers. Dendrimers have a wide spectrum of applications in biomedicine. Due to the empty space between the branches of the molecule, they can encapsulate drugs, and by conjugation and complexation to the surface groups, they are able to carry even larger drug molecules. Thus, dendrimers can be used as drug delivery systems. In addition, they have been used for skin application of several active molecules, either as topical or transdermal delivery. Suitable properties for (trans)dermal application have been demonstrated for dendrimers which consist of monomers with amine groups and are connected with amide bonds. The goal of this thesis was the preparation of dendrimers with these characteristics and the evaluation of their concentration influence to the permeability of 5-Fluorouracil (5-FU) to human...

Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: Dr. Georgios Paraskevopoulos, Ph.D. Consultant: Mgr. Anna Nová ková Author: Denisa Houšková Title of thesis: Effect of the generation of amino-decorated polyamidoamine dendrimers with ethylenediamine core at the (trans)dermal delivery of 5-fluorouracil. Dendrimers can be defined like highly branched, star-shaped macromolecules with nanometer-scale dimensions and unlimited applications in both biological and materials sciences. Polyamidoamine (PAMAM) dendrimers have been used to effectively enhance the (trans)dermal drug delivery of several active substances. Inspired by the structure of PAMAM dendrimers, a new class of dendrimers was designed having amino-functionalized periphery and ethylenediamine core. A repeating motif of bis(2-aminoethyl)glycine was used for generation growth up to the third generation. The new dendritic molecules of zero, first, second and third generation were tested for their ability to enhance the deposition of 5-fluorouracil in the different layers of human skin ex vivo by using Franz diffusion cells. The results suggest that the new dendrimers, at a concentration of 20 mg/mL in 60 % propylene glycol in water as vehicle, are able to deliver 5-fluorouracil at the...

This thesis aims to the assessment of methods used in in vitro analysis of dermal permeation and absorption of caffeine. Guarantee of standard processes during an experiment is essential for the rightness of results evaluation and interpretation. First part is focused on alternatives and different transport ways of substances through the skin barrier. As transdermal drug delivery offers an increasing number of advantages, the number of studies performing transdermal experiments with drug delivery grows up. On the other hand we are also able to observe or predict the risk of intoxication of individuals after exposure to different kinds of chemicals. The standard methods assessment is of great importance to obtain reproducible results. In this thesis, caffeine was chosen as a model hydrophilic compound. Skin barrier was simulated by dermatomed pig skin of two different thicknesses from ear and abdomen. Eight experimets were carried out with different types of skin using Franz cells in two types of dosing - finite and infinite. Experimental part of the thesis aims on actual determination of caffeine permeation . Measurements were taken in receptor fluid, in particular layers of the skin and on its surface. Spectrophotometry and HPLC analysis were used for the assessment. The ability of caffeine...

Cromolyn sodium (CS) is a mast cell stabilizer which has been used to treat systemic mastocytosis, allergic- and exercise-induced asthma, and allergic reactions induced by atopic dermatitis. Presently, CS is administered orally and intranasally, and with a short half-life and poor absorption, 4 to 8 doses are required daily for treatment. Developing a transdermal product for CS would eliminate such drawbacks that lead to inconsistent patient dosing and provide sustained therapeutic effects when administered via skin. Our long-term goal is to determine the feasibility of delivering CS through skin. However, a prerequisite for evaluating the performance of any transdermal system is to have a sensitive analytical method that can selectively detect and quantify the drug without any interference from compounds that may leach from skin during permeation studies. Therefore, our preliminary goal was to develop and validate such a method that can be employed for transdermal studies. The optimized liquid chromatography-mass spectrometry (LC-MS) method utilized a chromatographic separation which involved an isocratic mobile phase (10mM ammonium bicarbonate, pH 8.0, 90% and acetonitrile, 10%) at a flow rate of 0.2500 mL/min. Detection involved direct MS/MS channels with m/z 467.0255 (precursor) and m/z 379.0517 (fragment) with argon as the collision gas. CS calibrants were prepared in phosphate-buffered saline (PBS), pH 7.4, for validation (0.1, 0.25, 0.5, 0.75, 1, and 2.5 μg/mL). To ensure no skin interference, dermatomed porcine ear skin was minced, placed in PBS, and shaken for 15 hours to extract any possible interfering components. The extract was filtered and analyzed with the optimized LC-MS conditions. Calibrants were also analyzed over 3 days with each day examining 6 injections (20 μL) of each sample. Peak areas determined by LC-MS were used to construct calibration curves for CS and to calculate % error and % RSD to elucidate accuracy and precision of the method. Results showed CS retention time to be around 4.4 minutes with no interfering peak from skin extract, and linearity was observed between 0.1-2.5 μg/mL. Inter- and intra-day accuracy and precision of the method were within the acceptable limit of ±20% at the lower limit of quantitation and ±15% at other concentrations. Future studies will involve using the validated method for quantification of CS in skin permeation studies to investigate our long-term goal.

No description available.

Estudos recentes têm demonstrado o efeito das isoflavonas da soja, em especial da genisteína (GEN), aplicada topicamente, na prevenção do envelhecimento cutâneo. Esse efeito tem sido relacionado com as suas atividades inibidora de tirosina quinase, antioxidante e estrogênica. Neste contexto, o objetivo do presente trabalho foi desenvolver nanoemulsões de uso tópico contendo GEN. Em uma primeira etapa, foi validada metodologia para a quantificação da GEN por CLAE, utilizando um sistema isocrático com detecção no UV em 327 ou 270 nm. Na segunda etapa, nanoemulsões constituídas de GEN, lecitina de gema de ovo, triglicerídeos de cadeia média (TCMGEN) ou octildodecanol (ODDGEN) e água foram preparadas por emulsificação espontânea. Esse procedimento conduziu à obtenção de nanoemulsões monodispersas com diâmetro de gotícula de 263 e 282 nm, viscosidade de 1,5 e 1,8 cP e potencial zeta de -44 e -42 mV, para TCMGEN e ODDGEN, respectivamente. A quantidade de GEN associada com ambas as formulações foi próxima de 100 % (para 1 mg/mL). A reduzida solubilidade da GEN no TCM e ODD (230 e 138 μg/g, respectivamente) sugere o efeito da lecitina na sua associação com as nanoemulsões. Considerando que os estudos de DSC demonstraram a interação da GEN com TCM, ODD e lecitina, a GEN parece estar localizada tanto no núcleo oleoso como na interface das nanoemulsões. Em uma última etapa, foi realizado o estudo de permeação cutânea da GEN a partir das formulações utilizando células de difusão de Franz. Foi demonstrada a reduzida permeação da GEN (~ 7,5 μg.cm-2.h-1). Existe uma redução significativa da permeabilidade da GEN a partir dos núcleos óleos (~ 3,5 – 5 μg.cm-2.h-1) ou nanoemulsões (~ 3 – 3,5 μg.cm-2.h-1), indicando a afinidade da GEN pelos veículos utilizados. O conjunto dos resultados obtidos demonstra a influência dos componentes das formulações sobre as propriedades físico-químicas das nanoemulsões, bem como no perfil de permeação cutâneo da GEN. / Recent studies have shown the effect of soy isoflavones, especially genistein (GEN), topically administrated, in preventing skin aging. This effect has been related to tyrosine kinase inhibition, antioxidant and estrogenic activities. In this context, the aim of the present work was the development of topic nanoemulsions containing GEN. First, it has been validated an isocratic method to quantify GEN by HPLC with UV detection at 327 and 270 nm. In a second step, nanoemulsions composed by GEN, egg lecithin, medium chain triglycerides (TCMGEN) or octyldodecanol (ODDGEN) and water were prepared by spontaneous emulsification. This procedure yielded monodisperse emulsions with a typical mean droplet size of 263 and 282 nm, viscosity of 1.5 and 1.8 cP and ζ-potential -44 and -42 mV, for TCMGEN and ODDGEN, respectively. The amount of GEN associated with both formulations was close to 100 % (to 1 mg/mL). The low solubility of GEN in TCM and ODD (230 and 138 μg/g, respectively) suggests the role of lecithin on their association with nanoemulsions. Since DSC experiments have demonstrated GEN interactions with TCM, ODD and lecithin, GEN molecules seem to be located in to the oil core and at the interface of nanoemulsions. In a last step, the permeation of GEN from formulations using ear pigskin mounted in Franz diffusion cells was performed. It was shown that GEN permeation was low (~ 7.5 μg.cm-2.h-1). There was a significant reduction of the GEN permeability from oils (~ 3.5 - 5 μg.cm-2.h-1) or nanoemulsions (~ 3 – 3.5 μg.cm-2.h-1), showing the affinity of GEN to the vehicles. In conclusion, the overall results show the effect of the nanoemulsion components on both physicochemical properties of the nanoemulsions and GEN skin permeation profile.

Estudos recentes têm demonstrado o efeito das isoflavonas da soja, em especial da genisteína (GEN), aplicada topicamente, na prevenção do envelhecimento cutâneo. Esse efeito tem sido relacionado com as suas atividades inibidora de tirosina quinase, antioxidante e estrogênica. Neste contexto, o objetivo do presente trabalho foi desenvolver nanoemulsões de uso tópico contendo GEN. Em uma primeira etapa, foi validada metodologia para a quantificação da GEN por CLAE, utilizando um sistema isocrático com detecção no UV em 327 ou 270 nm. Na segunda etapa, nanoemulsões constituídas de GEN, lecitina de gema de ovo, triglicerídeos de cadeia média (TCMGEN) ou octildodecanol (ODDGEN) e água foram preparadas por emulsificação espontânea. Esse procedimento conduziu à obtenção de nanoemulsões monodispersas com diâmetro de gotícula de 263 e 282 nm, viscosidade de 1,5 e 1,8 cP e potencial zeta de -44 e -42 mV, para TCMGEN e ODDGEN, respectivamente. A quantidade de GEN associada com ambas as formulações foi próxima de 100 % (para 1 mg/mL). A reduzida solubilidade da GEN no TCM e ODD (230 e 138 μg/g, respectivamente) sugere o efeito da lecitina na sua associação com as nanoemulsões. Considerando que os estudos de DSC demonstraram a interação da GEN com TCM, ODD e lecitina, a GEN parece estar localizada tanto no núcleo oleoso como na interface das nanoemulsões. Em uma última etapa, foi realizado o estudo de permeação cutânea da GEN a partir das formulações utilizando células de difusão de Franz. Foi demonstrada a reduzida permeação da GEN (~ 7,5 μg.cm-2.h-1). Existe uma redução significativa da permeabilidade da GEN a partir dos núcleos óleos (~ 3,5 – 5 μg.cm-2.h-1) ou nanoemulsões (~ 3 – 3,5 μg.cm-2.h-1), indicando a afinidade da GEN pelos veículos utilizados. O conjunto dos resultados obtidos demonstra a influência dos componentes das formulações sobre as propriedades físico-químicas das nanoemulsões, bem como no perfil de permeação cutâneo da GEN. / Recent studies have shown the effect of soy isoflavones, especially genistein (GEN), topically administrated, in preventing skin aging. This effect has been related to tyrosine kinase inhibition, antioxidant and estrogenic activities. In this context, the aim of the present work was the development of topic nanoemulsions containing GEN. First, it has been validated an isocratic method to quantify GEN by HPLC with UV detection at 327 and 270 nm. In a second step, nanoemulsions composed by GEN, egg lecithin, medium chain triglycerides (TCMGEN) or octyldodecanol (ODDGEN) and water were prepared by spontaneous emulsification. This procedure yielded monodisperse emulsions with a typical mean droplet size of 263 and 282 nm, viscosity of 1.5 and 1.8 cP and ζ-potential -44 and -42 mV, for TCMGEN and ODDGEN, respectively. The amount of GEN associated with both formulations was close to 100 % (to 1 mg/mL). The low solubility of GEN in TCM and ODD (230 and 138 μg/g, respectively) suggests the role of lecithin on their association with nanoemulsions. Since DSC experiments have demonstrated GEN interactions with TCM, ODD and lecithin, GEN molecules seem to be located in to the oil core and at the interface of nanoemulsions. In a last step, the permeation of GEN from formulations using ear pigskin mounted in Franz diffusion cells was performed. It was shown that GEN permeation was low (~ 7.5 μg.cm-2.h-1). There was a significant reduction of the GEN permeability from oils (~ 3.5 - 5 μg.cm-2.h-1) or nanoemulsions (~ 3 – 3.5 μg.cm-2.h-1), showing the affinity of GEN to the vehicles. In conclusion, the overall results show the effect of the nanoemulsion components on both physicochemical properties of the nanoemulsions and GEN skin permeation profile.

Estudos recentes têm demonstrado o efeito das isoflavonas da soja, em especial da genisteína (GEN), aplicada topicamente, na prevenção do envelhecimento cutâneo. Esse efeito tem sido relacionado com as suas atividades inibidora de tirosina quinase, antioxidante e estrogênica. Neste contexto, o objetivo do presente trabalho foi desenvolver nanoemulsões de uso tópico contendo GEN. Em uma primeira etapa, foi validada metodologia para a quantificação da GEN por CLAE, utilizando um sistema isocrático com detecção no UV em 327 ou 270 nm. Na segunda etapa, nanoemulsões constituídas de GEN, lecitina de gema de ovo, triglicerídeos de cadeia média (TCMGEN) ou octildodecanol (ODDGEN) e água foram preparadas por emulsificação espontânea. Esse procedimento conduziu à obtenção de nanoemulsões monodispersas com diâmetro de gotícula de 263 e 282 nm, viscosidade de 1,5 e 1,8 cP e potencial zeta de -44 e -42 mV, para TCMGEN e ODDGEN, respectivamente. A quantidade de GEN associada com ambas as formulações foi próxima de 100 % (para 1 mg/mL). A reduzida solubilidade da GEN no TCM e ODD (230 e 138 μg/g, respectivamente) sugere o efeito da lecitina na sua associação com as nanoemulsões. Considerando que os estudos de DSC demonstraram a interação da GEN com TCM, ODD e lecitina, a GEN parece estar localizada tanto no núcleo oleoso como na interface das nanoemulsões. Em uma última etapa, foi realizado o estudo de permeação cutânea da GEN a partir das formulações utilizando células de difusão de Franz. Foi demonstrada a reduzida permeação da GEN (~ 7,5 μg.cm-2.h-1). Existe uma redução significativa da permeabilidade da GEN a partir dos núcleos óleos (~ 3,5 – 5 μg.cm-2.h-1) ou nanoemulsões (~ 3 – 3,5 μg.cm-2.h-1), indicando a afinidade da GEN pelos veículos utilizados. O conjunto dos resultados obtidos demonstra a influência dos componentes das formulações sobre as propriedades físico-químicas das nanoemulsões, bem como no perfil de permeação cutâneo da GEN. / Recent studies have shown the effect of soy isoflavones, especially genistein (GEN), topically administrated, in preventing skin aging. This effect has been related to tyrosine kinase inhibition, antioxidant and estrogenic activities. In this context, the aim of the present work was the development of topic nanoemulsions containing GEN. First, it has been validated an isocratic method to quantify GEN by HPLC with UV detection at 327 and 270 nm. In a second step, nanoemulsions composed by GEN, egg lecithin, medium chain triglycerides (TCMGEN) or octyldodecanol (ODDGEN) and water were prepared by spontaneous emulsification. This procedure yielded monodisperse emulsions with a typical mean droplet size of 263 and 282 nm, viscosity of 1.5 and 1.8 cP and ζ-potential -44 and -42 mV, for TCMGEN and ODDGEN, respectively. The amount of GEN associated with both formulations was close to 100 % (to 1 mg/mL). The low solubility of GEN in TCM and ODD (230 and 138 μg/g, respectively) suggests the role of lecithin on their association with nanoemulsions. Since DSC experiments have demonstrated GEN interactions with TCM, ODD and lecithin, GEN molecules seem to be located in to the oil core and at the interface of nanoemulsions. In a last step, the permeation of GEN from formulations using ear pigskin mounted in Franz diffusion cells was performed. It was shown that GEN permeation was low (~ 7.5 μg.cm-2.h-1). There was a significant reduction of the GEN permeability from oils (~ 3.5 - 5 μg.cm-2.h-1) or nanoemulsions (~ 3 – 3.5 μg.cm-2.h-1), showing the affinity of GEN to the vehicles. In conclusion, the overall results show the effect of the nanoemulsion components on both physicochemical properties of the nanoemulsions and GEN skin permeation profile.