Browsing by Author "Leite, Erica"
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- Development of ketoprofen delivery systems based on aqueous polyurethane dispersionsPublication . Leite, Erica; Fernandes, Isabel P.; Ayres, Eliane; Barreiro, M.F.; Silva-Cunha, ArmandoKetoprofen (2-(3-benzoylphenyl) propionic acid) is a non-steroidal anti-inflammatory drug (NSAID) used to treat a wide range of acute and chronic inflammatory diseases, e.g., rheumatoid arthritis, osteoarthritis and ankylosing spondylitis. Its prolonged oral administration is associated with several gastrointestinal reactions such as irritation and ulceration. In this context, ketoprofen is a good candidate for controlled release administration systems. This work aims to test the suitability of using aqueous polyurethane dispersions (PUDs) as the base vehicle for producing ketoprofen controlled release systems. Polyester (polycaprolactone, PCL) and polyether (polypropylene glycol, PPG) based PUDs have been synthesized by using a modified pre-polymer method. Two chain extenders have been assayed (ethylenediamina (EDA) and hydrazine monohydrate (HYD)).
- Dispersões aquosas de poliuretano como material base para o desenvolvimento de sistemas de libertação controlada de CetoprofenoPublication . Leite, Erica; Barreiro, M.F.; Cunha Júnior, Armando SilvaO cetoprofeno (ácido 2-(3-benzoilfenil) propiónico) é um anti-inflamatório não esteroidal (AINE) utilizado no tratamento de uma grande variedade de doenças inflamatórias agudas e crónicas incluindo a artrite reumatoide, osteoartrite e espondilite anquilosante. A sua administração oral prolongada está associada a diversas reações gastrointestinais, tais como irritações e ulcerações. Neste contexto, é importante desenvolver sistemas alternati-vos, nomeadamente sistemas de libertação controlada para administração oral, transdér-mica ou intradérmica. Este trabalho tem como objetivo testar a possibilidade de utilização de dispersões aquosas de poliuretano (PUDs) como material de suporte para a produção de sistemas de liberta-ção controlada de cetoprofeno. Numa primeira etapa, foram sintetizadas PUDs de base poliéster (policaprolactona, PCL) e poliéter (polipropileno-glicol, PPG) utilizando o méto-do de pré-polímero modificado. As dispersões obtidas foram caracterizadas em termos de pH, viscosidade, teor de sólidos e tamanho de partícula. Numa segunda etapa, foi testada a incorporação do cetoprofeno nas PDUs produzidas utilizando duas estratégias para incre-mentar a sua solubilidade em água: (i) utilização de um co-solvente (acetona, DMSO e HYD) e (ii) utilização de um surfactante não iónico (Tween 80). A incorporação foi testada para teores de 5% e 10% (razão fármaco/polímero, m/m). Os filmes produzidos pelo méto-do da evaporação do solvente foram avaliados quanto à sua homogeneidade e caracteriza-dos por FTIR e DSC. Numa terceira fase realizaram-se estudos de libertação em tampão de fosfato salino (PBS) de pH 7.5 tendo como objetivo avaliar a viabilidade de desenvolvimen-to de diferentes tipologias de dispositivos dependendo de um compromisso entre as pro-priedades dos filmes e o comportamento de libertação. Os resultados obtidos podem ajudar na seleção do material de base mais adequado para um determinado fim. Adicionalmente, e mais importante, comprovou-se a viabilidade de utilizar PUDs como material base para o desenvolvimento de sistemas de libertação con-trolada, utilizando como exemplo o cetoprofeno. A avaliação da toxicidade e da atividade anti-inflamatória dos filmes produzidos foi considerada estando em curso neste momento no grupo do Professor Armando Cunha Júnior.
- Production of chitosan based films enriched with essential oils for biomedical applicationsPublication . Vilas-Boas, Diana; Leite, Erica; Fernandes, Isabel P.; Amaral, Joana S.; Barreiro, M.F.Chitosan is a natural polysaccharide composed of β-(1-4) glucosamine and N-acetylglucosamine residues. Due to its safety and non-toxicity, biocompatibility, biodegradability and antimicrobial properties, its use in biomedical applications has been suggested in several studies. The objective of this work was the production of chitosan based films enriched with essential oils, to further improve the natural antimicrobial properties of chitosan. The films were produced at room temperature by evaporation. Different parameters were tested, namely the solution volume needed to prepare the films, the type of acid used to solubilize chitosan, the concentration of essential oil and the emulsifier type and concentration.
- Production of chitosan based films enriched with oregano essential oil for increased antibacterial activityPublication . Fernandes, Isabel P.; Leite, Erica; Vilas-Boas, Diana; Amaral, Joana S.; Barreiro, M.F.During the last years, there has been an increasing interest in developing bio-based active films to improve food safety, extend food shelf life and reduce the use of chemical preservatives [1]. Chitosan, a deacetylated derivative of chitin, is a linear polysaccharide consisting of β-(I⇒t4) glucosarnine and N-acetylglucosamine residues with potential to be used as a food packaging/coating material. This biopolymer can be used in a wide range of applications in the food industry due to several interesting properties such as its biodegradability, biocompatibility, non-toxicity, antimicrobial activity and versatile physical properties such as its film-forming capacity [I]. Recently, different strategies have been explored to improve its natural properties for the development of food packaging/coating materials with enhanced antimicrobial activity. In particular, the incorporation of essential oils (EO) with recognized antibacterial properties, as an alternative of synthetic preservatives, is a matter of great interest since they are generally perceived by consumers as being "natural" food additives.
- Production of chitosan based films enriched with oregano essential oil for increased antibacterial activityPublication . Fernandes, Isabel P.; Leite, Erica; Vilas-Boas, Diana; Amaral, Joana S.; Barreiro, M.F.During the last years, there has been an increasing interest in developing bio-based active films to improve food safety, extend food shelf life and reduce the use of chemical preservatives. Chitosan, a deacetylated derivative of chitin, is a linear polysaccharide consisting of -(1 4) glucosamine and N-acetylglucosamine residues with potential to be used as a food packaging/coating material. This biopolymer can be used in a wide range of applications in the food industry due to several interesting properties such as its biodegradability, biocompatibility, non-toxicity, antimicrobial activity and versatile physical properties such as its film-forming capacity. Recently, different strategies have been explored to improve its natural properties for the development of food packaging/coating materials with enhanced antimicrobial activity. In particular, the incorporation in chitosan films of essential oils (EO) with acknowledged antibacterial properties, as an alternative of synthetic preservatives, is a matter of great interest since they are generally perceived by consumers as being “natural” food additives. Thus, the objective of this work was the production of chitosan films enriched with oregano EO to further improve the natural antimicrobial properties of chitosan. The obtained films which were then evaluated for its antibacterial activity.