Title of thesis: Testing of adhesive properties of plasticized polyesters using rotational rheometer Author: Ogadah Chiazor Ugo Department: Pharmaceutical Technology Supervisor: PharmDr. Eva Šnejdrová, Ph.D. In this thesis, the rheological and adhesive properties of three polyesters intended for use as drug carriers in polymeric drug delivery systems were studied. The theoretical section summarizes the polymers used as drug carriers. Plasticizers, mechanism of action, types and uses and finally bioadhesion mechanism, application of the bioadhesive preparations, and methods of testing bioadhesion are reviewed. In the experimental section, ethyl salicylate, ethyl pyruvate and triethyl citrate were selected as the plasticizers to decrease the viscosity of the polyesters for easy processability, and setting of the optimal adhesive properties. Flow properties of the plasticized systems was measured with a rotational rheometer at temperature 37o C and a shear rate range from 0.10 to 100 s-1 . The analysis of the viscosity curves revealed that the resulting plasticized systems are mostly Newtonian. All tested plasticizers decrease the viscosity of the systems. The most effective is ethyl pyruvate. The adhesive properties were determined by the "pull away test" on the rotational rheometer, and evaluated as...

Introdução e objetivos: As nanocápsulas, uma vez que são produzidas com polímeros, representam sistemas mucoadesivos promissores. O uso desse tipo de sistema é importante no delineamento de medicamentos que vislumbrem a membrana sublingual como via de administração, devido ao constante fluxo de saliva. Em vista disso, esse trabalho tem como objetivos: estudar o efeito da nanoestruturação em nanocápsulas de polímeros de diferentes características iônicas, quanto as suas propriedades mucoadesivas, quando veiculadas em suspensão, hidrogel ou pós, e frente a distintas superfícies mucoadesivas (discos de mucina, mucosa vaginal ou mucosa bucal); desenvolver nanocápsulas contendo carvedilol, avaliando as suas propriedades mucoadesivas e perfil de permeação do fármaco em diferentes modelos de membrana sublingual; e produzir, a partir das nanocápsulas secas, comprimidos sublinguais contendo carvedilol nanoencapsulado. Metodologia: Nanocápsulas formadas por Eudragit® RS100, Eudragit® S100 ou poly(ε-caprolactona) [PCL] foram produzidas pelo método de deposição interfacial do polímero. Suas propriedades mucoadesivas foram avaliadas empregando analisador de textura. As nanocápsulas contendo carvedilol foram produzidas pelo mesmo método citado acima, utilizando Eudragit® RS100 e a PCL. A mucoadesão dessas nanocápsulas foi avaliada quanto a sua interação com moléculas de mucina, além do efeito da sua interação com a mucosa sublingual de porco na permanência do fármaco sobre a mucosa e na sua permeação, em presença de um fluxo salivar mimetizado. O transporte de carvedilol através de uma monocamada celular de células de epitélio oral (SCC4) também foi estudado. As suspensões de nanocápsulas foram, então, secas por aspersão e as propriedades das nanocápsulas redispersas foram reavaliadas. Na última etapa, foram produzidos comprimidos sublinguais pelo método de compressão direta, a partir dos pós desenvolvidos. Resultados: A mucoadesividade dos polímeros Eudragit® RS100, Eudragit® S100 e PCL foi potencializada pela sua estruturação em nanocápsulas. Dentre as formulações analisadas, as nanocápsulas catiônicas, formadas por Eudragit® RS100, veiculadas em gel, foram as que apresentaram melhores propriedades adesivas. Além disso, o processo de secagem não interferiu na adesividade das nanocápsulas originais. Em relação a superfície utilizada, a mucina se mostrou uma superfície mais adesiva comparada as mucosas suínas. Entretanto, a mucina reproduziu as diferenças observadas entre as formulações. As nanocápsulas contendo carvedilol interagiram bem com moléculas de mucina, sendo essa interação mais intensa para as nanocápsulas catiônicas [Eudragit® RS100], que para as aniônicas [PCL]. No entanto, ambas as nanocápsulas melhoraram o contato do carvedilol com a mucosa sublingual suína, o que fez com que mais fármaco permeasse através da mucosa, na presença de um fluxo salivar mimetizado, em comparação com uma solução do fármaco. Além disso, as nanocápsulas controlaram a permeação do fármaco através de mucosa sublingual de porco, bem como através de monocamadas de células SCC4. A partir destes resultados, as suspensões de nanocápsulas foram secas por aspersão. As nanopartículas foram recuperadas após redispersão aquosa dos pós e mantiveram suas propriedades mucoadesivas e biofarmacêuticas. Na sequência, os comprimidos foram produzidos como forma farmacêutica final. A presença de nanoestruturas foi observada nos comprimidos, as quais foram liberadas após total desintegração destes em saliva artificial. Além disso, a liberação do fármaco partir dos comprimidos contendo as nanocápsulas apresentou um perfil controlado comparado aos comprimidos contendo o fármaco livre, reforçando a manutenção da estrutura supramolecular das nanocápsulas nos comprimidos. Conclusão: As nanocápsulas produzidas com Eudragit® RS100, Eudragit® S100 ou PCL apresentaram boas características mucoadesivas. As, nanocápsulas de Eudragit® RS100 e PCL também melhoraram a interação do carvedilol com a membrana sublingual de porco. Em ambos os estudos, um melhor desempenho mucoadesivo foi observado para as nanocápsulas catiônicas. Além disso, o carvedilol apresentou boa permeação através de mucosa sublingual suína e através de monocama celular de células de epitélio oral. Ainda, a secagem por aspersão das suspensões de nanocápsulas não alterou significativamente as suas propriedades. A compressão direta dos pós secos por aspersão produziu comprimidos inovadores contendo um sistema nanotecnológico mucoadesivo para administração sublingual de carvedilol, como um nanomedicamento. / Introduction and objectives: Nanocapsules may represent promissing mucoadhesive systems since they are produced with polymers. The use of these systems is very important for drug administration by the sublingual route due to the constantly salivary flux in the oral cavity. In view of this, the objectives of this study were: to study the effect of the nanostructuration in nanocapsules on the mucoadhesiveness of polymers with different charge surface and the effect of the vehicle (suspension, hydrogel, and powder) on the mucoadhesiveness of nanocapsules as well as the effect of different mucosal surfaces (mucin, vaginal mucosa, and buccal mucosa); to develop carvedilol-loaded nanocapsules and to evaluate their mucoadhesive properties and drug permeation profiles using different models of sublingual membrane; and to produce sublingual tablets using spray-dried carvedilol-loaded nanocapsules. Methods: Eudragit®RS100, Eudragit®S100 or poly(ε-caprolactone) [PCL] nanocapsules were produced by interfacial deposition of the polymer method. Their mucoadhesiveness were evaluated by tensile stress tester. Carvedilol-loaded nanocapsules were produced by the method cited above and using Eudragit® RS100 or PCL as polymers. Mucoadhesiveness of nanocapsules were studied analyzing their interaction with mucin molecules and analyzing the effect of their interaction with porcine sublingual mucosa on drug retention as well on the amount of drug permeated to the receptor fluid in the presence of simulated salivary flux. The transport of carvedilol across monolayers of oral epithelial cells (SCC4) was also evaluated. In the next step, nanocapsules suspensions were spray-dried and the properties of redispersed nanocapsules were evaluated. In the last step, sublingual tablets were produced by direct compression using the spray-dried nanocapsules. Results: Mucoadhesiveness of Eudragit® RS100, Eudragit® S100 and PCL were improved by their structuration in nanocapsules. Among the tested formulations, the cationic Eudragit® RS100 nanocapsules formulated as a hydrogel showed the best behavior. Moreover, the drying process did not interfer in the adhesiveness of original nanocapsules. Regarding the surface substrate, mucin discs were more adhesive than porcine mucosas. However, mucin was able to reproduce the differences observed between the formulations. Carvedilol-loaded nanocapsules interacted with mucin molecules and this interaction was more intense for cationic Eudragit® RS100 nanocapsules than for anionic PCL nanocapsules. However, both nanocapsules increased the amount of drug retained on porcine sublingual mucosa and improved the amount of drug permeated through mucosa, in comparison to the drug solution, in presence of a mimetic salivary flux was present. Furthermore, nanocapsules were able to control the drug permeation across porcine sublingual and through SCC4 monolayer. Subsequently, suitable powders were obtained by spray-drying. The original nanoparticles were recovered after aqueous redispersion of powders and the maintenance of their mucoadhesiveness and biopharmaceutics properties was observed. Moreover, sublingual tablets were produced as a final pharmaceutical form. The presence of nanometric particles in the tablets was observed and they were released after tablet disintegration in artififcial saliva. The drug was released by a controlled way from tablets containing nanocapsules when compared to tablets containing the non-encapsulated drug, reinforcing the maintenance of supramolecular structure of nanocapsules in the tablets. Conclusion: The Eudragit® RS100, Eudragit® S100 and PCL nanocapsules showed good mucoadhesive characteristics. Moreover, Eudragit® RS100 and PCL nanocapsules improved the carvedilol interaction with porcine sublingual mucosa. In both studies, cationic nanocapsules showed the best mucoadhesive performance. Additionally, carvedilol showed a good permeation across porcine sublingual mucosa and through oral epithelial cells monolayer. The spray-drying process did not change the properties of the original aqueous nanocapsules. Furthermore, their direct compression produced innovative tablets containing a mucoadhesive nanotechnological system for sublingual administration of carvedilol as a nanomedicine.

This thesis investigated the perception of salt taste in two novel strategies for inclusion of NaCl in liquid foods: water-in-oil (w/o) emulsions and mucoadhesive biopolymer solutions. The major factors influencing w/o emulsion stability and perception were evaluated and a response surface model was developed. The amount of dispersed aqueous phase was the most significant factor affecting stability and perception. NaCl stabilized the emulsions and depressed salt sensory perception at elevated concentrations due to its interaction with the emulsifier polyglycerol polyricinoleate. Future research should elaborate events during oral processing of w/o emulsions. Biopolymer mucoadhesive character and concentration effects were also investigated. Mucoadhesion did not enhance salt taste. Above c*, there was a significant depression of sensory intensity, enhanced in polymers with hyperentanglements in solution. The depressive concentration effect may mask the effects of mucoadhesion. Future research should also inspect the influence of thickened hydrocolloid microstructure on perception. / The Advanced Foods and Materials Network

Introdução e objetivos: As nanocápsulas, uma vez que são produzidas com polímeros, representam sistemas mucoadesivos promissores. O uso desse tipo de sistema é importante no delineamento de medicamentos que vislumbrem a membrana sublingual como via de administração, devido ao constante fluxo de saliva. Em vista disso, esse trabalho tem como objetivos: estudar o efeito da nanoestruturação em nanocápsulas de polímeros de diferentes características iônicas, quanto as suas propriedades mucoadesivas, quando veiculadas em suspensão, hidrogel ou pós, e frente a distintas superfícies mucoadesivas (discos de mucina, mucosa vaginal ou mucosa bucal); desenvolver nanocápsulas contendo carvedilol, avaliando as suas propriedades mucoadesivas e perfil de permeação do fármaco em diferentes modelos de membrana sublingual; e produzir, a partir das nanocápsulas secas, comprimidos sublinguais contendo carvedilol nanoencapsulado. Metodologia: Nanocápsulas formadas por Eudragit® RS100, Eudragit® S100 ou poly(ε-caprolactona) [PCL] foram produzidas pelo método de deposição interfacial do polímero. Suas propriedades mucoadesivas foram avaliadas empregando analisador de textura. As nanocápsulas contendo carvedilol foram produzidas pelo mesmo método citado acima, utilizando Eudragit® RS100 e a PCL. A mucoadesão dessas nanocápsulas foi avaliada quanto a sua interação com moléculas de mucina, além do efeito da sua interação com a mucosa sublingual de porco na permanência do fármaco sobre a mucosa e na sua permeação, em presença de um fluxo salivar mimetizado. O transporte de carvedilol através de uma monocamada celular de células de epitélio oral (SCC4) também foi estudado. As suspensões de nanocápsulas foram, então, secas por aspersão e as propriedades das nanocápsulas redispersas foram reavaliadas. Na última etapa, foram produzidos comprimidos sublinguais pelo método de compressão direta, a partir dos pós desenvolvidos. Resultados: A mucoadesividade dos polímeros Eudragit® RS100, Eudragit® S100 e PCL foi potencializada pela sua estruturação em nanocápsulas. Dentre as formulações analisadas, as nanocápsulas catiônicas, formadas por Eudragit® RS100, veiculadas em gel, foram as que apresentaram melhores propriedades adesivas. Além disso, o processo de secagem não interferiu na adesividade das nanocápsulas originais. Em relação a superfície utilizada, a mucina se mostrou uma superfície mais adesiva comparada as mucosas suínas. Entretanto, a mucina reproduziu as diferenças observadas entre as formulações. As nanocápsulas contendo carvedilol interagiram bem com moléculas de mucina, sendo essa interação mais intensa para as nanocápsulas catiônicas [Eudragit® RS100], que para as aniônicas [PCL]. No entanto, ambas as nanocápsulas melhoraram o contato do carvedilol com a mucosa sublingual suína, o que fez com que mais fármaco permeasse através da mucosa, na presença de um fluxo salivar mimetizado, em comparação com uma solução do fármaco. Além disso, as nanocápsulas controlaram a permeação do fármaco através de mucosa sublingual de porco, bem como através de monocamadas de células SCC4. A partir destes resultados, as suspensões de nanocápsulas foram secas por aspersão. As nanopartículas foram recuperadas após redispersão aquosa dos pós e mantiveram suas propriedades mucoadesivas e biofarmacêuticas. Na sequência, os comprimidos foram produzidos como forma farmacêutica final. A presença de nanoestruturas foi observada nos comprimidos, as quais foram liberadas após total desintegração destes em saliva artificial. Além disso, a liberação do fármaco partir dos comprimidos contendo as nanocápsulas apresentou um perfil controlado comparado aos comprimidos contendo o fármaco livre, reforçando a manutenção da estrutura supramolecular das nanocápsulas nos comprimidos. Conclusão: As nanocápsulas produzidas com Eudragit® RS100, Eudragit® S100 ou PCL apresentaram boas características mucoadesivas. As, nanocápsulas de Eudragit® RS100 e PCL também melhoraram a interação do carvedilol com a membrana sublingual de porco. Em ambos os estudos, um melhor desempenho mucoadesivo foi observado para as nanocápsulas catiônicas. Além disso, o carvedilol apresentou boa permeação através de mucosa sublingual suína e através de monocama celular de células de epitélio oral. Ainda, a secagem por aspersão das suspensões de nanocápsulas não alterou significativamente as suas propriedades. A compressão direta dos pós secos por aspersão produziu comprimidos inovadores contendo um sistema nanotecnológico mucoadesivo para administração sublingual de carvedilol, como um nanomedicamento. / Introduction and objectives: Nanocapsules may represent promissing mucoadhesive systems since they are produced with polymers. The use of these systems is very important for drug administration by the sublingual route due to the constantly salivary flux in the oral cavity. In view of this, the objectives of this study were: to study the effect of the nanostructuration in nanocapsules on the mucoadhesiveness of polymers with different charge surface and the effect of the vehicle (suspension, hydrogel, and powder) on the mucoadhesiveness of nanocapsules as well as the effect of different mucosal surfaces (mucin, vaginal mucosa, and buccal mucosa); to develop carvedilol-loaded nanocapsules and to evaluate their mucoadhesive properties and drug permeation profiles using different models of sublingual membrane; and to produce sublingual tablets using spray-dried carvedilol-loaded nanocapsules. Methods: Eudragit®RS100, Eudragit®S100 or poly(ε-caprolactone) [PCL] nanocapsules were produced by interfacial deposition of the polymer method. Their mucoadhesiveness were evaluated by tensile stress tester. Carvedilol-loaded nanocapsules were produced by the method cited above and using Eudragit® RS100 or PCL as polymers. Mucoadhesiveness of nanocapsules were studied analyzing their interaction with mucin molecules and analyzing the effect of their interaction with porcine sublingual mucosa on drug retention as well on the amount of drug permeated to the receptor fluid in the presence of simulated salivary flux. The transport of carvedilol across monolayers of oral epithelial cells (SCC4) was also evaluated. In the next step, nanocapsules suspensions were spray-dried and the properties of redispersed nanocapsules were evaluated. In the last step, sublingual tablets were produced by direct compression using the spray-dried nanocapsules. Results: Mucoadhesiveness of Eudragit® RS100, Eudragit® S100 and PCL were improved by their structuration in nanocapsules. Among the tested formulations, the cationic Eudragit® RS100 nanocapsules formulated as a hydrogel showed the best behavior. Moreover, the drying process did not interfer in the adhesiveness of original nanocapsules. Regarding the surface substrate, mucin discs were more adhesive than porcine mucosas. However, mucin was able to reproduce the differences observed between the formulations. Carvedilol-loaded nanocapsules interacted with mucin molecules and this interaction was more intense for cationic Eudragit® RS100 nanocapsules than for anionic PCL nanocapsules. However, both nanocapsules increased the amount of drug retained on porcine sublingual mucosa and improved the amount of drug permeated through mucosa, in comparison to the drug solution, in presence of a mimetic salivary flux was present. Furthermore, nanocapsules were able to control the drug permeation across porcine sublingual and through SCC4 monolayer. Subsequently, suitable powders were obtained by spray-drying. The original nanoparticles were recovered after aqueous redispersion of powders and the maintenance of their mucoadhesiveness and biopharmaceutics properties was observed. Moreover, sublingual tablets were produced as a final pharmaceutical form. The presence of nanometric particles in the tablets was observed and they were released after tablet disintegration in artififcial saliva. The drug was released by a controlled way from tablets containing nanocapsules when compared to tablets containing the non-encapsulated drug, reinforcing the maintenance of supramolecular structure of nanocapsules in the tablets. Conclusion: The Eudragit® RS100, Eudragit® S100 and PCL nanocapsules showed good mucoadhesive characteristics. Moreover, Eudragit® RS100 and PCL nanocapsules improved the carvedilol interaction with porcine sublingual mucosa. In both studies, cationic nanocapsules showed the best mucoadhesive performance. Additionally, carvedilol showed a good permeation across porcine sublingual mucosa and through oral epithelial cells monolayer. The spray-drying process did not change the properties of the original aqueous nanocapsules. Furthermore, their direct compression produced innovative tablets containing a mucoadhesive nanotechnological system for sublingual administration of carvedilol as a nanomedicine.

Introdução e objetivos: As nanocápsulas, uma vez que são produzidas com polímeros, representam sistemas mucoadesivos promissores. O uso desse tipo de sistema é importante no delineamento de medicamentos que vislumbrem a membrana sublingual como via de administração, devido ao constante fluxo de saliva. Em vista disso, esse trabalho tem como objetivos: estudar o efeito da nanoestruturação em nanocápsulas de polímeros de diferentes características iônicas, quanto as suas propriedades mucoadesivas, quando veiculadas em suspensão, hidrogel ou pós, e frente a distintas superfícies mucoadesivas (discos de mucina, mucosa vaginal ou mucosa bucal); desenvolver nanocápsulas contendo carvedilol, avaliando as suas propriedades mucoadesivas e perfil de permeação do fármaco em diferentes modelos de membrana sublingual; e produzir, a partir das nanocápsulas secas, comprimidos sublinguais contendo carvedilol nanoencapsulado. Metodologia: Nanocápsulas formadas por Eudragit® RS100, Eudragit® S100 ou poly(ε-caprolactona) [PCL] foram produzidas pelo método de deposição interfacial do polímero. Suas propriedades mucoadesivas foram avaliadas empregando analisador de textura. As nanocápsulas contendo carvedilol foram produzidas pelo mesmo método citado acima, utilizando Eudragit® RS100 e a PCL. A mucoadesão dessas nanocápsulas foi avaliada quanto a sua interação com moléculas de mucina, além do efeito da sua interação com a mucosa sublingual de porco na permanência do fármaco sobre a mucosa e na sua permeação, em presença de um fluxo salivar mimetizado. O transporte de carvedilol através de uma monocamada celular de células de epitélio oral (SCC4) também foi estudado. As suspensões de nanocápsulas foram, então, secas por aspersão e as propriedades das nanocápsulas redispersas foram reavaliadas. Na última etapa, foram produzidos comprimidos sublinguais pelo método de compressão direta, a partir dos pós desenvolvidos. Resultados: A mucoadesividade dos polímeros Eudragit® RS100, Eudragit® S100 e PCL foi potencializada pela sua estruturação em nanocápsulas. Dentre as formulações analisadas, as nanocápsulas catiônicas, formadas por Eudragit® RS100, veiculadas em gel, foram as que apresentaram melhores propriedades adesivas. Além disso, o processo de secagem não interferiu na adesividade das nanocápsulas originais. Em relação a superfície utilizada, a mucina se mostrou uma superfície mais adesiva comparada as mucosas suínas. Entretanto, a mucina reproduziu as diferenças observadas entre as formulações. As nanocápsulas contendo carvedilol interagiram bem com moléculas de mucina, sendo essa interação mais intensa para as nanocápsulas catiônicas [Eudragit® RS100], que para as aniônicas [PCL]. No entanto, ambas as nanocápsulas melhoraram o contato do carvedilol com a mucosa sublingual suína, o que fez com que mais fármaco permeasse através da mucosa, na presença de um fluxo salivar mimetizado, em comparação com uma solução do fármaco. Além disso, as nanocápsulas controlaram a permeação do fármaco através de mucosa sublingual de porco, bem como através de monocamadas de células SCC4. A partir destes resultados, as suspensões de nanocápsulas foram secas por aspersão. As nanopartículas foram recuperadas após redispersão aquosa dos pós e mantiveram suas propriedades mucoadesivas e biofarmacêuticas. Na sequência, os comprimidos foram produzidos como forma farmacêutica final. A presença de nanoestruturas foi observada nos comprimidos, as quais foram liberadas após total desintegração destes em saliva artificial. Além disso, a liberação do fármaco partir dos comprimidos contendo as nanocápsulas apresentou um perfil controlado comparado aos comprimidos contendo o fármaco livre, reforçando a manutenção da estrutura supramolecular das nanocápsulas nos comprimidos. Conclusão: As nanocápsulas produzidas com Eudragit® RS100, Eudragit® S100 ou PCL apresentaram boas características mucoadesivas. As, nanocápsulas de Eudragit® RS100 e PCL também melhoraram a interação do carvedilol com a membrana sublingual de porco. Em ambos os estudos, um melhor desempenho mucoadesivo foi observado para as nanocápsulas catiônicas. Além disso, o carvedilol apresentou boa permeação através de mucosa sublingual suína e através de monocama celular de células de epitélio oral. Ainda, a secagem por aspersão das suspensões de nanocápsulas não alterou significativamente as suas propriedades. A compressão direta dos pós secos por aspersão produziu comprimidos inovadores contendo um sistema nanotecnológico mucoadesivo para administração sublingual de carvedilol, como um nanomedicamento. / Introduction and objectives: Nanocapsules may represent promissing mucoadhesive systems since they are produced with polymers. The use of these systems is very important for drug administration by the sublingual route due to the constantly salivary flux in the oral cavity. In view of this, the objectives of this study were: to study the effect of the nanostructuration in nanocapsules on the mucoadhesiveness of polymers with different charge surface and the effect of the vehicle (suspension, hydrogel, and powder) on the mucoadhesiveness of nanocapsules as well as the effect of different mucosal surfaces (mucin, vaginal mucosa, and buccal mucosa); to develop carvedilol-loaded nanocapsules and to evaluate their mucoadhesive properties and drug permeation profiles using different models of sublingual membrane; and to produce sublingual tablets using spray-dried carvedilol-loaded nanocapsules. Methods: Eudragit®RS100, Eudragit®S100 or poly(ε-caprolactone) [PCL] nanocapsules were produced by interfacial deposition of the polymer method. Their mucoadhesiveness were evaluated by tensile stress tester. Carvedilol-loaded nanocapsules were produced by the method cited above and using Eudragit® RS100 or PCL as polymers. Mucoadhesiveness of nanocapsules were studied analyzing their interaction with mucin molecules and analyzing the effect of their interaction with porcine sublingual mucosa on drug retention as well on the amount of drug permeated to the receptor fluid in the presence of simulated salivary flux. The transport of carvedilol across monolayers of oral epithelial cells (SCC4) was also evaluated. In the next step, nanocapsules suspensions were spray-dried and the properties of redispersed nanocapsules were evaluated. In the last step, sublingual tablets were produced by direct compression using the spray-dried nanocapsules. Results: Mucoadhesiveness of Eudragit® RS100, Eudragit® S100 and PCL were improved by their structuration in nanocapsules. Among the tested formulations, the cationic Eudragit® RS100 nanocapsules formulated as a hydrogel showed the best behavior. Moreover, the drying process did not interfer in the adhesiveness of original nanocapsules. Regarding the surface substrate, mucin discs were more adhesive than porcine mucosas. However, mucin was able to reproduce the differences observed between the formulations. Carvedilol-loaded nanocapsules interacted with mucin molecules and this interaction was more intense for cationic Eudragit® RS100 nanocapsules than for anionic PCL nanocapsules. However, both nanocapsules increased the amount of drug retained on porcine sublingual mucosa and improved the amount of drug permeated through mucosa, in comparison to the drug solution, in presence of a mimetic salivary flux was present. Furthermore, nanocapsules were able to control the drug permeation across porcine sublingual and through SCC4 monolayer. Subsequently, suitable powders were obtained by spray-drying. The original nanoparticles were recovered after aqueous redispersion of powders and the maintenance of their mucoadhesiveness and biopharmaceutics properties was observed. Moreover, sublingual tablets were produced as a final pharmaceutical form. The presence of nanometric particles in the tablets was observed and they were released after tablet disintegration in artififcial saliva. The drug was released by a controlled way from tablets containing nanocapsules when compared to tablets containing the non-encapsulated drug, reinforcing the maintenance of supramolecular structure of nanocapsules in the tablets. Conclusion: The Eudragit® RS100, Eudragit® S100 and PCL nanocapsules showed good mucoadhesive characteristics. Moreover, Eudragit® RS100 and PCL nanocapsules improved the carvedilol interaction with porcine sublingual mucosa. In both studies, cationic nanocapsules showed the best mucoadhesive performance. Additionally, carvedilol showed a good permeation across porcine sublingual mucosa and through oral epithelial cells monolayer. The spray-drying process did not change the properties of the original aqueous nanocapsules. Furthermore, their direct compression produced innovative tablets containing a mucoadhesive nanotechnological system for sublingual administration of carvedilol as a nanomedicine.

Effective delivery of drugs to the anterior segment of the eye is notoriously inefficient due to the anatomical barriers in place. Topical administration is the most common method of drug delivery to the anterior segment. When applied to the ocular surface, topical solutions encounter barriers such as lacrimal drainage, rapid tear turnover, and reflex blinking which result in < 5% of instilled therapeutic reaching the intended tissue. One potential method to evade some of these anatomical barriers and improve the delivery of therapeutics is the use of mucoadhesive nanoparticles. These materials are designed to encapsulate a relevant ocular therapeutic and provide a means of maintaining the vehicle on the ocular surface by adhering to the mucin layer of the tear film. To this end, the work presented herein describes the design, characterization, and testing of a novel mucoadhesive polymeric nano-micelle ocular drug delivery system. The base polymer used was selected from a system that has been previously used in the Sheardown Lab. It was composed of poly(D,L-lactide)-block-poly(methacrylic acid-co-3-(acrylamido)phenylboronic acid) (PLA-b-P(MAA-co-3-AAPBA); LMP-20). The formulation was modified to replace the 3-AAPBA monomer, which contains phenyl boronic acid as the mucoadhesive component, with a preactivated thiol monomer (pyridyl disulfide ethyl methacrylate; PDSMA) to generate a novel polymer (LMS-20) to investigate the potential for drug incorporation and mucoadhesion. Modifications of the polymer were made with small thiol molecules cysteamine (Cys; LMC-20), glutathione (GSH; LMG-20), and N-acetyl cysteine (NAC; LMA-20) with a goal of reducing cytotoxicity associated with the 2-pyridinethione leaving group. Synthesis of the PDSMA monomer, LMS-20 and LMP-20 polymers, and modified polymers LMC-20, LMG-20, and LMA-20 were confirmed by 1H NMR. LMA-20 was chosen for further examination as it contained the most relevant thiol modification for ocular applications and was capable of nanoprecipitation to form aqueous micelles with previously developed methods. Micelles were formed from LMA-20 and LMP-20, with spherical morphology as confirmed by TEM. Effective diameters of 64 ± 5 nm and 72 ± 3 nm are reported for LMA-20 and LMP-20, respectively, as confirmed by DLS. Critical micelle concentration for LMA-20 of 217 mg/L was found via a pyrene fluorescence study, significantly lower than the concentration of intended application. LMA-20 and LMP-20 are predicted to be mucoadhesive based on results of zeta-potential studies. However, oscillatory rheology studies were inconclusive based on a negative rheological synergism. LMA-20 micelles loaded with 0.16% (w/w) Cyclosporine-A were able to provide sustained release of drug up to 3 days in vitro. These results suggest the possible future use of these preactivated thiomer-based materials for the delivery of therapeutics to the anterior segment. / Thesis / Master of Applied Science (MASc)

Most marketed formulations for treating anterior ocular conditions are topical, with conventional eyedrops representing the most utilized modality. However, due to the natural clearance mechanisms of the eye, less than 5% of an applied dose remains bioavailable following administration. To overcome the shortcomings associated with conventional eyedrops, a series of enzymatically degradable, mucoadhesive thermogels were developed. Thermogels can be applied as a solution, like a conventional eyedrops, but gel against the heat of eye. To avoid obstructing vision, these thermogels were designed to be instilled within the inferior fornix of the eye. In these studies, the base thermogelling polymer (pNAM) was crosslinked with the natural polymer chitosan. Not only does crosslinking strengthen the typically weak thermogels, but chitosan can be enzymatically degraded by lysozyme, the highest concentration protein found in tear fluid. Therefore, the developed thermogels can be applied to the inferior fornix and degrade over multiple days. A limitation of applying materials to the inferior fornix is they tend to be poorly retained. To anchor the developed thermogels within the inferior fornix, the mucoadhesive properties were tailored based on the chitosan utilized as well as the inclusion of a disulfide monomer capable of covalently bonding with the natural mucosal layer covering the surface of the eye. The disulfide bridging monomer could be further conjugated with therapeutic components which were released as a function of mucosal interaction. Conjugates investigated included cysteamine for treating cystinosis, n-acetyl cysteine for treating dry eye, the adhesion peptide RGDC as a model peptide/protein, and polyethylene glycol for modulating material properties. The release of the drugs Ketotifen Fumarate, for treating allergic conjunctivitis, and atropine, for treating myopia, were also investigated. The safety of the developed thermogels were studied both in vivo and extensively in vitro utilizing both rat and rabbit models. / Dissertation / Doctor of Philosophy (PhD) / Topical eyedrops are the most utilized treatment option for the vast majority of ocular diseases. However, eyedrops are largely ineffective with less than 5% of an applied dose reaching the desired cite of action. Therefore, eyedrops need to be frequently reapplied. To overcome these limitations, an eyedrop was developed which can be applied as a liquid but gels against the heat of the eye. This gel allows for prolonged drug release over multiple days, greatly increasing drug efficacy as well as patient comfort and compliance. To prevent obstructing vision, these gels can be applied under the lower eyelid. To keep these gels retained under the lower eyelid, they were designed to anchor to the natural mucus layer which covers the surface of eye. The developed eyedrops represent a significant advancement in ocular care; bettering the convenience, comfort, and effectiveness for patients of a topical formulation compared to traditional eyedrops.

Oral delivery of insulin used for the management of Type 1 Diabetes could be referred to as one of the major long term goals of diabetes research. However, the bioavailability of orally administered insulin is significantly compromised by enzymatic degradation in the GI tract and poor enteral absorption of the protein due to its macromolecular size and hydrophilicity. Nano-sized polymer-protein polyelectrolyte complexes (PECS) formed by electrostatic interactions between insulin and Polyallylamine-based polymers at pH 7.4 have been adapted to facilitate oral insulin delivery. Polyallylamine (15kDa) was quaternised by methylation of its primary amines using methyl iodide to yield quaternised Paa (QPaa). Average level of polymer quaternisation was determined by elemental analysis and was found to be 72 ± 2mol%. Subsequent thiolation of Paa and QPaa using two different thiolation procedures involving carbodiimide mediated conjugation to N-acetylcysteine (NAC) and modification of the polymers using 2-iminothiolane hydrochloride yielded their respective NAC and 4-thiobutylamidine (TBA) conjugates: Paa-NAC/QPaa-NAC and Paa-TBA/QPaa-TBA. Estimation of the free thiol content of these thiomers by iodometric titration showed that both Paa-NAC and QPaa-NAC displayed 60 ± 1.2 and 60 ± 4.3ìmol free thiol groups per gram polymer, while Paa-TBA and QPaa-TBA conjugates displayed 490 ± 18 and 440 ± 21ìmol free thiol groups per gram polymer respectively. Mixing optimal mass ratios of each polymer and insulin in Tris buffer at pH 7.4 resulted in the formation of soluble nanocomplexes. Complexes were characterised by transmittance measurements, particle size analysis, zeta potential, complexation efficiency, and transmission electron microscopy (TEM). Stable polymer-insulin complexes were observed to have hydrodynamic sizes between 50-200nm, positively charged zeta potential values ranging between 20-40mV and high insulin complexation efficiency (> 90%). Complexation of insulin with TBA conjugates however appeared to alter insulin conformation affecting the detection of complexed insulin by HPLC. TEM analysis revealed the formation of bilayered nanovessicles as well as conventional single-layered nanoparticles on complexation of insulin with QPaa and thiolated Paa/QPaa derivatives. In-vitro assessments of enzyme-protective effect of QPaa, Paa-NAC and QPaa-NAC insulin complexes showed that when compared to a free insulin control, all the aforementioned complexes could protect insulin from degradation by trypsin and á-chymotrypsin, but not from pepsin. In-vitro mucin adsorption assays showed that all polymers exhibited a similar mucoadhesive profile with their corresponding insulin PEC, with thiolated Paa derivatives adsorbing >20% more mucin than Paa. Thiolation of QPaa did not result in a noticeable improvement in its mucoadhesive capacity indicating that polymer-mucin thiol-disulphide interactions may be hindered by the presence of quaternary groups. The IC50 of each polymer was determined by MTT assays carried out on Caco-2 cells with or without the inclusion of a 24-hour cell recovery period. An MTT assay conducted without a recovery period indicated that quaternisation of Paa was associated with a 6-fold improvement in its IC50; also cells subjected to a 24-hour recovery period following treatment with QPaa (0.001-4mgml-1) showed no signs of toxicity. Thiolation of Paa resulted in slight (≤ 2 fold) improvements in IC50, while thiolation of QPaa resulted in a decrease in IC50 values obtained both with and without a cell recovery period. Each polymer was subsequently labelled with rhodamine B isothiocyanate (RBITC) and complexed with fluorescein isothiocyanate (FITC)-insulin. Monitoring uptake of these complexes by Caco-2 cells using fluorescence microscopy with DAPI staining indicated that uptake of QPaa and QPaa-TBA complexes was mainly intracellular being localised within the perinuclear area of cells highlighted by DAPI. Hence, intracellular uptake of PECS by Caco-2 cells was enhanced by Paa quaternisation and TBA-based thiolation of QPaa.

Resumo: A zidovudina (AZT) é o fármaco antiretroviral mais utilizado no tratamento da AIDS, porém possui baixa biodisponibilidade, pois sofre intenso metabolismo hepático. Para alcançar concentrações plasmáticas efetivas são requeridas doses altas e freqüentes, as quais podem chegar a níveis tóxicos. A via nasal tem sido proposta como uma rota alternativa para administração de fármacos que sofrem metabolismo pré-sistêmico, pois favorece a absorção direta para circulação sanguínea; porém, ela possui mecanismos de depuração mucociliar, os quais podem eliminar rapidamente a formulação da cavidade nasal. Sistemas de liberação mucoadesivos podem promover o contato prolongado entre a formulação e os sítios de absorção da cavidade nasal, retardando a depuração mucociliar. Alguns sistemas estabilizados por tensoativos, capazes de formar diferentes estruturas liotrópicas líquido cristalinas, têm sido propostos para aumentar o tempo de contato de formulações com as mucosas. Estes sistemas, ao entrar em contato com os fluidos aquosos que compõem o muco, se ordenam em cristais líquidos (CLs), formando uma matriz de liberação do fármaco. O objetivo deste trabalho foi desenvolver sistemas capazes de formar CLs, como potenciais sistemas mucoadesivos para administração intranasal do AZT. A caracterização por microscopia de luz polarizada e SAXS mostrou que microemulsões (MEs) formadas por AC205/ácido oléico/água formam CLs com a adição tanto de água como de fluído nasal simulado (FNS). As MEs foram capazes de incorporar cerca de 50 mg.g-1 de AZT. A mucoadesão foi avaliada por ensaios de reologia oscilatória, em que a adição de fase aquosa aumentou os módulos elásticos dos sistemas, e pela medida da força para remover as formulações a partir de um disco de mucina, obtidas através de um analisador de textura. Ensaios de liberação in vitro em... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Zidovudine (AZT) is the most widely used drug in AIDS treatment; however, AZT shows low oral bioavailability, since it suffers extensive hepatic metabolism. In order to maintain therapeutic levels, large doses have to be given frequently, which may reach toxic levels. The nasal route has been exploited as an alternative route of drugs that suffer first pass metabolism, as it ensures the direct drug absorption to blood circulation; however, the nasal route has mucociliary clearance mechanisms which can quickly remove the formulation of the nasal cavity. Mucoadhesive drug delivery systems can improve residence time of formulation in the nasal cavity absorption sites, delaying mucociliary clearance. Some surfactants systems which are able to form different liotropic liquid crystalline structures have been explored as a strategy to increase formulation residence time on the mucosa. When these systems are placed in physiologic aqueous environment, they can form a drug delivery matrix. The aim of this work was to develop systems capable of forming CLs as potential intranasal AZT mucoadhesive systems. The polarized light microscopy and SAXS characterization showed that microemulsions (MEs) composed by AC205/oleic acid/water form CLs with the addition of either water or simulated nasal fluid (FNS). The MEs were able to incorporate about 50 mg.g-1 of AZT. The mucoadhesion was evaluated both by oscillatory rheology, in which aqueous phase addition increased the elastic modulus of the systems, and by measurement of the necessary force to remove the formulations from mucin disc, obtained through texture analyzer. In vitro Franz' Cell drug release assay showed, according to the Weibull model, that phase transition sustained AZT release. These results suggest that the systems in hand have great potential for nasal AZT administration. / Orientador: Maria Palmira Daflon Gremião / Coorientador: Victor Hugo Vitorino Sarmento / Banca: Maria Palmira Daflon Gremião / Banca: Marcela Longhi / Banca: Rosângela Itri / Mestre

O tratamento farmacológico de patologias bucais é conduzido, geralmente, por via de adminis-tração local. No entanto, devido ao pouco tempo de permanência do fármaco no local de ação, esse tratamento pode ser bastante comprometido. Assim, este trabalho teve por objetivo o de-senvolvimento de formas farmacêuticas que proporcionem a liberação local de triancinolona na cavidade oral. Foram produzidos filmes e comprimidos mucoadesivos a partir de polímeros naturais como gelana e pectina. Os filmes bucais foram preparados por meio de evaporação do solvente (solvent casting) utilizando diferentes quantidades de polímeros. As matérias-primas e os filmes foram caracterizados fisico quimicamente utilizando espectroscopia vibracional (in-fravermelho com transformada de Fourier e Raman) e difração de raios X. As propiedades físicas e mecânicas dos filmes também foram avaliadas. Além disso, realizou-se os ensaios de mucoadesividade e de dissolução do fármaco. Os comprimidos foram preparados por com-pressão direta usando como base os polímeros naturais. Diferentes parâmetros em relação as misturas e as formulações foram avaliados tais como as propriedades de fluxo dos pós consti-tuintes, peso médio, dureza, friabilidade e desintegração. Em relação aos filmes bucais, estes foram obtidos com sucesso através de um método simples, sem a utilização de agentes reticu-lantes, ácidos ou solventes orgânicos. Todos apresentaram bons resultados nas propriedades avaliadas, no entanto as formulações com quantidades intermediarias de polímeros foram as melhores. Dentre as formulações de comprimidos preparadas, apenas 4 apresentaram boas ca-racterísticas, no entanto, os resultados dos ensaios de dissolução mostraram que estas formula-ções têm capacidade de agir como sistema de liberação controlada de fármacos. / Pharmacological treatment of oral pathologies is usually conducted by local administration. However, due to the short time the drug stays in the site of action, this treatment can be quite compromised. Thus, the objective of this work was to develop pharmaceutical forms that pro-vide the local release of triamcinolone in the oral cavity. Mucoadhesive films and tablets were made from natural polymers such as gellan and pectin. The buccal films were prepared by sol-vent casting using different amounts of polymers. The raw materials and films were characte-rized physically chemically using vibrational spectroscopy (FTIR and Raman) and X-ray diffraction. The physical and mechanical properties of the films were also evaluated. In addi-tion, the mucoadhesive and drug dissolution tests were performed. The tablets were prepared by direct pressing with the natural polymers. Different parameters in relation to mixtures and formulations were evaluated such as the flow properties of the constituent powders, average weight, hardness, friability and disintegration. In relation to oral films, these were successfully obtained by a simple method, without the use of crosslinking agents, acids or organic solvents. All presented good results in the evaluated properties, however the formulations with interme-diate amounts of polymers were the best. Among the tablet formulations prepared, only 4 sho-wed good characteristics, however, the dissolution test results showed that these formulations have the ability to act as a controlled drug delivery system.