No abstract

Dexamethasone-loaded poly(lactide-co-glycolide) (PLGA) devices are commonly used as model systems for controlled release. In this study, PLGA nanoparticles containing dexamethasone acetate were prepared by a nanoprecipitation technique in the absence of organochlorine solvents and were characterized by their mean size, f potential, scanning electron microscopy, and differential scanning calorimetry to develop a controlled release system. The analytical method for the quantification of dexamethasone acetate by high-performance liquid chromatography was validated. The results show that it was possible to prepare particles at a nanometric size because the average diameter of the drug-loaded PLGA particles was 540 6 4 nm with a polydispersity index of 0.07 6 0.01 and a f potential of 22.5 6 0.3 mV. These values remained stable for at least 7 months. The drug encapsulation efficiency was 48%. In vitro tests showed that about 25% of the drug was released in 48 h.

No abstract

Polysaccharides have been widely used for the development of drug delivery systems. These systems can be physicochemically modified to enhance their stabilities and control their drug release profiles. However, such modifications cannot alter their biocompatibility or toxicity. Herein, four structurally modified sodium alginate/carboxymethylcellulose blends are synthesized and loaded with prednisone, and the effects of the modifications on their hydrolytic degradation rates, biocompatibilities, toxicities, and drug release profiles are investigated. All the blends are ionically cross‐linked with Ca2+ and Fe3+. Blend 1 is not modified further, blend 2 is additionally reinforced with 8% w/w of cellulose nanocrystals, blend 3 is treated with epoxidized linseed oil to develop a hydrophobic layer, and blend 4 is chemically cross‐linked with epichlorohydrin. Blends 2 and 4 exhibit similar physicochemical characteristics, appropriate hydrolytic degradation rates and drug release patterns, as well as biocompatibility and non‐toxicity. In‐vitro studies using the osteoblasts and CAM assay demonstrate that blends 2 and 4 are also biocompatible and non‐toxic. In contrast, blend 1 exhibits the highest drug release rate, followed by blend 3.

Sistemas de liberação controlada de fármacos têm por objetivos principais minimizar a necessidade de doses tóxicas e propiciar melhor controle da liberação do princípio ativo ao longo do tempo quando comparado à forma convencional de administração. Neste trabalho foi preparado um sistema de liberação controlada do fármaco mebendazol (MDZ), que apresenta baixa absorção gastrointestinal pela sua baixa solubilidade em água, a partir de uma matriz polimérica biodegradável formada por alginato de sódio. O teste de intumescimento e a avaliação temporal da liberação do ativo in vitro foram realizados em meio que simula as condições do corpo humano. A avaliação da resistência ao meio fisiológico pela matriz polimérica com MDZ incorporado mostrou que a mesma permaneceu por mais de 72 h no meio fisiológico, enquanto que a avaliação do comportamento de dissolução e liberação do MDZ durante 8 h mostrou-se satisfatória com a liberação do ativo de forma lenta de gradual, o que demonstra o potencial dessa matriz para ser usado como um dispositivo oral de liberação controlada desse fármaco.