RESUMO
Self-assembly of amphiphilic polysaccharides provides a positive outlook for drug delivery systems without the need for solvents or surfactants. Various polymeric amphiphilic polysaccharides undergo intramolecular or intermolecular associations in water. This type of association, promoted by hydrophobic segments, led to the formation of various drug delivery systems such as micelles, nanoparticles, liposomes and hydrogels. Here, we review a selection of the most important amphiphilic polysaccharides used as drug delivery systems and their pharmaceutical applications. Attention focuses on amphiphilic chitosan owing to its unique properties such as excellent biocompatibility, non-toxicity and antimicrobial and bioadhesive properties.
Assuntos
Portadores de Fármacos/química , Polissacarídeos/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/toxicidade , Quitosana/química , Quitosana/farmacologia , Quitosana/toxicidade , Portadores de Fármacos/farmacologia , Portadores de Fármacos/toxicidade , Sistemas de Liberação de Medicamentos , Hidrogéis , Interações Hidrofóbicas e Hidrofílicas , Micelas , Medicina Molecular , Estrutura Molecular , Nanopartículas , Polissacarídeos/farmacologia , Polissacarídeos/toxicidadeRESUMO
Diastereomeric reduction of nonactivated, hindered ß-keto and chiral ß-iminoesters are described. The influence of a α-stereocontrolled center on the efficiency and stereoselectivity of the reduction was studied. Reaction conditions were optimized to synthesize ß-hydroxy- and ß-aminoesters in good yields. In the case of chiral ß-iminoesters, influence of matched/mismatched diastereomeric pairs has been assessed.
