A via de administração vaginal pode ser considerada uma alternativa para diversos tratamentos, tanto de ação farmacológica local como sistêmica. No entanto, o tempo de permanência do fármaco no local da aplicação e a eficácia esperada representam um desafio para o desenvolvimento de formulações. O objetivo deste trabalho foi desenvolver nanocápsulas de superfície catiônica (EUDRAGIT® RS 100) ou aniônica (EUDRAGIT® S 100), contendo ou não o marcador de fluorescência Vermelho do Nilo como um modelo de fármaco lipofílico, e incorporar essas partículas em hidrogéis de quitosana, a fim de aumentar o tempo de residência da formulação na mucosa vaginal, devido às propriedades mucoadesivas desse polímero. Diversas formulações foram preparadas com concentrações crescentes de quitosana e analisadas em termos de pH e comportamento reológico, a fim de selecionar a mais adequada para aplicação vaginal. Os hidrogéis foram produzidos com quitosana 2,5% p/p, com ou sem nanocápsulas. Foi avaliada a aderência (mucoadesividade e perfil lavabilidade) e a capacidade de penetração (microscopia confocal e extração seguido de quantificação do vermelho do nilo) das formulações quando aplicadas em mucosa vaginal de porcas. As suspensões de nanocápsulas apresentaram diâmetro em torno de 200 nm e potencial zeta entre +13 mV (NC-RS) e -13 mV( NC-S) e valores de pH entre 5,1 e 6,2. A formulação de quitosana apresentou viscosidade característica e pH ácido (em torno de 4,5), ideal para aplicação vaginal. Os testes de mucoadesão mostraram que as formulações propostas contendo nanocápsulas poliméricas apresentaram maior adesividade em mucosa vaginal em comparação com a formulação composta somente de quitosana. Através do experimento de lavabilidade não foram encontradas diferenças significativas entre as formulações. No entanto, as técnicas de microscopia confocal e a quantificação após a extração de fluorescência a partir da mucosa demonstraram uma maior penetração de vermelho do nilo quando nanoencapsulado, especialmente em nanocápsulas catiônicas. As formulações desenvolvidas com base no veículo do hidrogel de quitosana e nanocápsulas poliméricas, especialmente as nanocápsulas catiônicas, demonstraram aplicabilidade para a entrega de substâncias hidrofóbicas pela via vaginal. Palavras-chave: quitosana, nanocápsuas, via vaginal, EUDRAGIT® RS100, EUDRAGIT® S100. / The vaginal route of administration might be an alternative for several treatments, either for local or systemic pharmacological effect. However, the permanence of the drug at the site of application and its expected effectiveness represent a challenge in the development of formulations. Thus, the objective of this work was to develop nanocapsules with cationic or anionic surface charge, containing or not nile red as a model of lipophilic substance, and to incorporate such particles into chitosan vehicle in order to increase the residence time of the formulation due to chitosan mucoadhesive properties. Several formulations prepared with increasing chitosan concentrations were analyzed in terms of pH and rheological behaviour in order to select the most suitable one for vaginal application. Gel formulations were produced with chitosan at 2.5% w/w, with or without nanocapsules. The adhesion (tensile stress test and washability profile) and penetration enhancement properties (confocal microscopy- CLSM and extraction followed by quantification) of the formuations, when applied on porcine vaginal mucosa, were evaluated. The nanocapsule suspensions presented adequate properties and pH values around 5.1 and 6.2. The chitosan formulation presented a characteristic viscosity and an acid pH (around 4.5), which is suitable for vaginal application. Mucoadhesion tests showed that the proposed formulations containing polymeric nanocapsules had higher adhesion to the vaginal mucosa in comparison with the formulation containing only chitosan. The washability evaluation showed no significant differences between the formulations. However, the confocal microscopy and the fluorescence quantification after extraction from the mucosa showed higher penetration of nile red when nanoencapsulated, especially into cationic-charged nanocapsules. The formulations developed, based on chitosan gel vehicle and polymeric nanocapsules, especially the cationic nanocapsules, demonstrated applicability for the vaginal delivery of hydrophobic substances.

A via de administração vaginal pode ser considerada uma alternativa para diversos tratamentos, tanto de ação farmacológica local como sistêmica. No entanto, o tempo de permanência do fármaco no local da aplicação e a eficácia esperada representam um desafio para o desenvolvimento de formulações. O objetivo deste trabalho foi desenvolver nanocápsulas de superfície catiônica (EUDRAGIT® RS 100) ou aniônica (EUDRAGIT® S 100), contendo ou não o marcador de fluorescência Vermelho do Nilo como um modelo de fármaco lipofílico, e incorporar essas partículas em hidrogéis de quitosana, a fim de aumentar o tempo de residência da formulação na mucosa vaginal, devido às propriedades mucoadesivas desse polímero. Diversas formulações foram preparadas com concentrações crescentes de quitosana e analisadas em termos de pH e comportamento reológico, a fim de selecionar a mais adequada para aplicação vaginal. Os hidrogéis foram produzidos com quitosana 2,5% p/p, com ou sem nanocápsulas. Foi avaliada a aderência (mucoadesividade e perfil lavabilidade) e a capacidade de penetração (microscopia confocal e extração seguido de quantificação do vermelho do nilo) das formulações quando aplicadas em mucosa vaginal de porcas. As suspensões de nanocápsulas apresentaram diâmetro em torno de 200 nm e potencial zeta entre +13 mV (NC-RS) e -13 mV( NC-S) e valores de pH entre 5,1 e 6,2. A formulação de quitosana apresentou viscosidade característica e pH ácido (em torno de 4,5), ideal para aplicação vaginal. Os testes de mucoadesão mostraram que as formulações propostas contendo nanocápsulas poliméricas apresentaram maior adesividade em mucosa vaginal em comparação com a formulação composta somente de quitosana. Através do experimento de lavabilidade não foram encontradas diferenças significativas entre as formulações. No entanto, as técnicas de microscopia confocal e a quantificação após a extração de fluorescência a partir da mucosa demonstraram uma maior penetração de vermelho do nilo quando nanoencapsulado, especialmente em nanocápsulas catiônicas. As formulações desenvolvidas com base no veículo do hidrogel de quitosana e nanocápsulas poliméricas, especialmente as nanocápsulas catiônicas, demonstraram aplicabilidade para a entrega de substâncias hidrofóbicas pela via vaginal. Palavras-chave: quitosana, nanocápsuas, via vaginal, EUDRAGIT® RS100, EUDRAGIT® S100. / The vaginal route of administration might be an alternative for several treatments, either for local or systemic pharmacological effect. However, the permanence of the drug at the site of application and its expected effectiveness represent a challenge in the development of formulations. Thus, the objective of this work was to develop nanocapsules with cationic or anionic surface charge, containing or not nile red as a model of lipophilic substance, and to incorporate such particles into chitosan vehicle in order to increase the residence time of the formulation due to chitosan mucoadhesive properties. Several formulations prepared with increasing chitosan concentrations were analyzed in terms of pH and rheological behaviour in order to select the most suitable one for vaginal application. Gel formulations were produced with chitosan at 2.5% w/w, with or without nanocapsules. The adhesion (tensile stress test and washability profile) and penetration enhancement properties (confocal microscopy- CLSM and extraction followed by quantification) of the formuations, when applied on porcine vaginal mucosa, were evaluated. The nanocapsule suspensions presented adequate properties and pH values around 5.1 and 6.2. The chitosan formulation presented a characteristic viscosity and an acid pH (around 4.5), which is suitable for vaginal application. Mucoadhesion tests showed that the proposed formulations containing polymeric nanocapsules had higher adhesion to the vaginal mucosa in comparison with the formulation containing only chitosan. The washability evaluation showed no significant differences between the formulations. However, the confocal microscopy and the fluorescence quantification after extraction from the mucosa showed higher penetration of nile red when nanoencapsulated, especially into cationic-charged nanocapsules. The formulations developed, based on chitosan gel vehicle and polymeric nanocapsules, especially the cationic nanocapsules, demonstrated applicability for the vaginal delivery of hydrophobic substances.

A via de administração vaginal pode ser considerada uma alternativa para diversos tratamentos, tanto de ação farmacológica local como sistêmica. No entanto, o tempo de permanência do fármaco no local da aplicação e a eficácia esperada representam um desafio para o desenvolvimento de formulações. O objetivo deste trabalho foi desenvolver nanocápsulas de superfície catiônica (EUDRAGIT® RS 100) ou aniônica (EUDRAGIT® S 100), contendo ou não o marcador de fluorescência Vermelho do Nilo como um modelo de fármaco lipofílico, e incorporar essas partículas em hidrogéis de quitosana, a fim de aumentar o tempo de residência da formulação na mucosa vaginal, devido às propriedades mucoadesivas desse polímero. Diversas formulações foram preparadas com concentrações crescentes de quitosana e analisadas em termos de pH e comportamento reológico, a fim de selecionar a mais adequada para aplicação vaginal. Os hidrogéis foram produzidos com quitosana 2,5% p/p, com ou sem nanocápsulas. Foi avaliada a aderência (mucoadesividade e perfil lavabilidade) e a capacidade de penetração (microscopia confocal e extração seguido de quantificação do vermelho do nilo) das formulações quando aplicadas em mucosa vaginal de porcas. As suspensões de nanocápsulas apresentaram diâmetro em torno de 200 nm e potencial zeta entre +13 mV (NC-RS) e -13 mV( NC-S) e valores de pH entre 5,1 e 6,2. A formulação de quitosana apresentou viscosidade característica e pH ácido (em torno de 4,5), ideal para aplicação vaginal. Os testes de mucoadesão mostraram que as formulações propostas contendo nanocápsulas poliméricas apresentaram maior adesividade em mucosa vaginal em comparação com a formulação composta somente de quitosana. Através do experimento de lavabilidade não foram encontradas diferenças significativas entre as formulações. No entanto, as técnicas de microscopia confocal e a quantificação após a extração de fluorescência a partir da mucosa demonstraram uma maior penetração de vermelho do nilo quando nanoencapsulado, especialmente em nanocápsulas catiônicas. As formulações desenvolvidas com base no veículo do hidrogel de quitosana e nanocápsulas poliméricas, especialmente as nanocápsulas catiônicas, demonstraram aplicabilidade para a entrega de substâncias hidrofóbicas pela via vaginal. Palavras-chave: quitosana, nanocápsuas, via vaginal, EUDRAGIT® RS100, EUDRAGIT® S100. / The vaginal route of administration might be an alternative for several treatments, either for local or systemic pharmacological effect. However, the permanence of the drug at the site of application and its expected effectiveness represent a challenge in the development of formulations. Thus, the objective of this work was to develop nanocapsules with cationic or anionic surface charge, containing or not nile red as a model of lipophilic substance, and to incorporate such particles into chitosan vehicle in order to increase the residence time of the formulation due to chitosan mucoadhesive properties. Several formulations prepared with increasing chitosan concentrations were analyzed in terms of pH and rheological behaviour in order to select the most suitable one for vaginal application. Gel formulations were produced with chitosan at 2.5% w/w, with or without nanocapsules. The adhesion (tensile stress test and washability profile) and penetration enhancement properties (confocal microscopy- CLSM and extraction followed by quantification) of the formuations, when applied on porcine vaginal mucosa, were evaluated. The nanocapsule suspensions presented adequate properties and pH values around 5.1 and 6.2. The chitosan formulation presented a characteristic viscosity and an acid pH (around 4.5), which is suitable for vaginal application. Mucoadhesion tests showed that the proposed formulations containing polymeric nanocapsules had higher adhesion to the vaginal mucosa in comparison with the formulation containing only chitosan. The washability evaluation showed no significant differences between the formulations. However, the confocal microscopy and the fluorescence quantification after extraction from the mucosa showed higher penetration of nile red when nanoencapsulated, especially into cationic-charged nanocapsules. The formulations developed, based on chitosan gel vehicle and polymeric nanocapsules, especially the cationic nanocapsules, demonstrated applicability for the vaginal delivery of hydrophobic substances.

The aim of this work was to prepare, characterize and evaluate the in vitro cytotoxicity of Eudragit S100® nanocapsules (NC) containing ketoprofen. The nanostructured suspensions were prepared in triplicate by the method of interfacial deposition of preformed polymer. Caprilic/capric triglyceride or rosehip oil were used as the oil core in the preparation of such formulations. Previously, tests of swelling/dissolution of the films of Eudragit S100® were performed and showed the feasibility of using both oils as the core of the NC. The results of the physico-chemical characterization of the systems (pH, size, zeta potential, content, encapsulation efficiency) showed no significant differences between the various types of formulations. The concentration of ketoprofen in the formulations was very close to the theoretical concentration, indicating no loss or degradation of the drug during the preparation process. The encapsulation efficiency of ketoprofen in NC was higher than 90%. The particle size of the formulations was found in the range of 173-197 nm, which is in accordance to the method of preparation employed. Regarding the in vitro release, the mathematical analysis of the profiles showed a first order kinetics with drug diffusion as release mechanism. In order to evaluate the influence of the oil component in the ketoprofen photodegradation, samples were exposed to UVC radiation. The photodegradation was less evident in the rosehip oil NC, probably due to the greatest antioxidant potential of this oil. The in vitro cytotoxicity assay evaluated the viability of 3T3 cell line against four concentrations of ketoprofen (1, 10, 50 and 100 μM) for 24 and 48 hours. After 48 hours of exposure, there was a reduction in cell viability in all tested groups. However, this decrease was not significantly different from the control group. Thus, the prepared formulations can be considered promising alternatives for the delivery of ketoprofen in inflammatory diseases such as rheumatoid arthritis. / O objetivo deste trabalho foi preparar, caracterizar e avaliar in vitro a citotoxicidade de nanocápsulas (NC) de Eudragit S100® contendo cetoprofeno. As suspensões nanoestruturadas foram preparadas em triplicata pelo método de deposição interfacial do polímero pré-formado. Triglicerídeos de cadeia média (TCM) ou óleo de rosa mosqueta (ORM) foram utilizados como núcleo oleoso na preparação de tais formulações. Previamente, foram realizados testes de inchamento/dissolução dos filmes de Eudragit S100®, os quais revelaram a viabilidade do emprego de ambos os óleos como núcleo das NC. Os resultados da caraterização físico-química dos sistemas (pH, tamanho, potencial zeta, teor, eficiência de encapsulamento) não demonstraram diferenças consideráveis entre os diferentes tipos de formulações. O teor de cetoprofeno nas suspensões nanoestruturadas foi muito próximo à concentração teórica, indicando ausência de perda ou degradação do fármaco durante o processo de preparação. Obteve-se uma taxa de associação do cetoprofeno às NC superior a 90%. O tamanho de partícula nas formulações encontrou-se na faixa de 173 a 197 nm, resultados compatíveis com o método de preparação empregado. Quanto à liberação in vitro, a análise matemática dos perfis demonstrou uma cinética de primeira ordem com difusão do fármaco como mecanismo de liberação. A fim de avaliar a influência do componente oleoso frente à fotodegradação do cetoprofeno, amostras foram expostas à radiação UVC. A fotodegradação foi menos evidente nas NC contendo ORM como núcleo, possivelmente pelo maior potencial antioxidante deste óleo. O teste de citotoxicidade in vitro avaliou a sobrevivência de fibroblastos da linhagem 3T3 frente a quatro concentrações de cetoprofeno (1, 10, 50 e 100 μM) em 24 e 48 horas. Após 48h de exposição, observou-se uma redução da viabilidade celular para todos os grupos testados. Contudo, esta diminuição não foi diferente significativamente do grupo controle. Desta forma, as formulações preparadas podem ser consideradas promissoras para veiculação do cetoprofeno em doenças como a artrite reumatoide.

Controlled release formulations offer many advantages over conventional dosage forms. These include reduced plasma fluctuations and improved patient comp1i:nce. Complex controlled release formulations such as those with enteric release properties, often require additional steps in the production phase. The costs and economic impact associated with these complex controlled release dosage formulations often outweigh the immediate benefits. Thus the development of an economic method to produce controlled release particles is of great importance especially in third world countries. In controlled release formulations, the drug is generally dispersed throughout a polymer matrix. The rate of drug release is often determined by the viscosity or complexity of the polymer matrix through which the drug needs to diffuse in order to be released. With enteric release the polymer coating, insoluble in an acidic environment is often applied in the final phase of production. Chitosan is a versatile polymer of natural origin with many favourable characteristics. These include its safety, biocompatibility, and biodegradability. Simple methods can be applied and modified to produce controlled release particles form chitosan. The effect of modern controlled release polymers such as Aqoat AS-HF, Eudragit SlOO and Kollidon SR was investigated. Chitosan beads and chitosan-polymer beads, as well as chitosan granules and chitosan-polymer granules, were prepared and investigated as possible controlled release formulations. Ketoprofen was chosen as the model drug. Chitosan beads and chitosan-polymer beads were prepared by inotropic gelation in tripolyphosphate. Chitosan granules and chitosan-polymer matrix granules were prepared by binding chitosan with an acetic acid solution as a granulating system. The beads and granules appeared differed in appearance as well as in the results obtained from various experiments. Granules prepared in the study did not appear to be effective with regards to enteric and controlled release. Beads prepared form Kollidon SR appeared to be effective with regards to enteric and controlled release, with Kollidon 1% and 5% w/v chitosan beads achieving good drug loading of up to 73.13% and releasing less than 15 % of the total drug content in 0.1 M HCI after 60 minutes. Drug release continued steadily for up to 360 minutes in pH 7.2. It was concluded that Kollidon SR loaded chitosan beads nay be a viable controlled release dosage form with enteric release properties, and that future experiments, possibly with lower polymer concentrations, are worthwhile / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2006.

Controlled release formulations offer many advantages over conventional dosage forms. These include reduced plasma fluctuations and improved patient comp1i:nce. Complex controlled release formulations such as those with enteric release properties, often require additional steps in the production phase. The costs and economic impact associated with these complex controlled release dosage formulations often outweigh the immediate benefits. Thus the development of an economic method to produce controlled release particles is of great importance especially in third world countries. In controlled release formulations, the drug is generally dispersed throughout a polymer matrix. The rate of drug release is often determined by the viscosity or complexity of the polymer matrix through which the drug needs to diffuse in order to be released. With enteric release the polymer coating, insoluble in an acidic environment is often applied in the final phase of production. Chitosan is a versatile polymer of natural origin with many favourable characteristics. These include its safety, biocompatibility, and biodegradability. Simple methods can be applied and modified to produce controlled release particles form chitosan. The effect of modern controlled release polymers such as Aqoat AS-HF, Eudragit SlOO and Kollidon SR was investigated. Chitosan beads and chitosan-polymer beads, as well as chitosan granules and chitosan-polymer granules, were prepared and investigated as possible controlled release formulations. Ketoprofen was chosen as the model drug. Chitosan beads and chitosan-polymer beads were prepared by inotropic gelation in tripolyphosphate. Chitosan granules and chitosan-polymer matrix granules were prepared by binding chitosan with an acetic acid solution as a granulating system. The beads and granules appeared differed in appearance as well as in the results obtained from various experiments. Granules prepared in the study did not appear to be effective with regards to enteric and controlled release. Beads prepared form Kollidon SR appeared to be effective with regards to enteric and controlled release, with Kollidon 1% and 5% w/v chitosan beads achieving good drug loading of up to 73.13% and releasing less than 15 % of the total drug content in 0.1 M HCI after 60 minutes. Drug release continued steadily for up to 360 minutes in pH 7.2. It was concluded that Kollidon SR loaded chitosan beads nay be a viable controlled release dosage form with enteric release properties, and that future experiments, possibly with lower polymer concentrations, are worthwhile / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2006.

Made available in DSpace on 2015-02-24T17:42:52Z (GMT). No. of bitstreams: 1 ThalesRFP_DISSERT.pdf: 5363462 bytes, checksum: 16f2d3a123870a2d8c63de00ac4bf689 (MD5) Previous issue date: 2014-02-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Helicobacter pylori is the main cause of gastritis, gastroduodenal ulcer disease and gastric cancer. The most recommended treatment for eradication of this bacteria often leads to side effects and patient poor compliance, which induce treatment failure. Magnetic drug targeting is a very efficient method that overcomes these drawbacks through association of the drug with a magnetic compound. Such approach may allow such systems to be placed slowed down to a specific target area by an external magnetic field. This work reports a study of the synthesis and characterization of polymeric magnetic particles loaded with the currently used antimicrobial agents for the treatment of Helicobacter pylori infections, aiming the production of magnetic drug delivery system by oral route. Optical microscopy, scanning electron microscopy, transmission electron microscopy, x-ray powder diffraction, nitrogen adsorption/desorption isotherms and vibrating sample magnetometry revealed that the magnetite particles, produced by the co-precipitation method, consisted of a large number of aggregated nanometer-size crystallites (about 6 nm), creating superparamagnetic micrometer with high magnetic susceptibility particles with an average diameter of 6.8 ? 0.2 μm. Also, the polymeric magnetic particles produced by spray drying had a core-shell structure based on magnetite microparticles, amoxicillin and clarithromycin and coated with Eudragit? S100. The system presented an average diameter of 14.2 ? 0.2 μm. The amount of magnetite present in the system may be tailored by suitably controlling the suspension used to feed the spray dryer. In the present work it was 2.9% (w/w). The magnetic system produced may prove to be very promising for eradication of Helicobacter pylori infections / A Helicobacter pylori ? a principal causa de gastrites, ?lceras gastroduodenais e c?ncer g?strico. O esquema terap?utico de primeira escolha para a erradica??o desse pat?geno leva muitas vezes a elevado n?mero de rea??es adversas, baixa ades?o do paciente e consequentemente falha na terap?utica. A vetoriza??o magn?tica ? uma t?cnica bastante difundida na literatura que visa minimizar esses problemas, atrav?s da associa??o de f?rmacos a n?cleos magn?ticos direcionando para o local de a??o por interm?dio de campo magn?tico externo. O presente trabalho relata o estudo da s?ntese e caracteriza??o de part?culas polim?ricas magn?ticas contendo os mais frequentes antimicrobianos (amoxicilina e claritromicina) usados no tratamento de infec??es por Helicobacter pylori, objetivando a produ??o de um sistema para vetoriza??o magn?tica por via oral. Granulometria baseada no di?metro de Feret, microscopia eletr?nica de varredura e transmiss?o, difratometria de raio-x, isotermas de adsor??o/dessor??o de nitrog?nio e magnetometria de amostra vibrante revelaram que as part?culas de magnetita, produzidas pelo m?todo da coprecipita??o, consistem em grande n?mero de agregados de cristalitos de tamanhos nanom?tricos (da ordem de 6 nm) os quais formam part?culas microm?tricas superparamagn?ticas de alta susceptibilidade magn?tica, tendo formato irregular com di?metro m?dio de 6,8 ? 0,2 μm. Os n?cleos magn?ticos foram revestidos por pol?mero (Eudragit? S100) em conjunto com amoxicilina e claritromicina (forma polim?rfica II) sendo obtido micropart?culas n?cleo-camada de formato irregular, pela t?cnica de secagem por aspers?o (spray dryer), com um di?metro m?dio de 14,2 ? 0,2 μm. A quantidade de magnetita presente no sistema pode ser adaptada pelo controle da suspens?o inicial usada na alimenta??o do spray dryer. No presente trabalho o conte?do magn?tico final foi estimado em 2,9 % (p/p). Com base nos resultados obtidos, o sistema magn?tico produzido pode se tornar bastante promissor na erradica??o de infec??es por Helicobacter pylori