RESUMO
Chitosan-poly(acrylic acid) (CS-PAA) nanoparticles, to be used as ophthalmic drug carrier, were successfully prepared using template polymerization of acrylic acid (AA) in a chitosan solution. When the polymerization was done at 70 degrees C for 45 min with a CS/AA weight ratio of 1:1, the surface structure of the prepared nanoparticles was most stable with the smallest mean diameter (92.0 +/- 7.5 nm) and a stable zeta potential (25.5 +/- 2.6 mV) in a buffer solution (pH 4.5). The size of the nanoparticles dramatically increased with the pH value of the medium. Both in vitro and in vivo studies revealed that the prepared nanoparticle suspension was better at sustaining the release of pilocarpine than either simulated tear fluid or commercial eye drops.
Assuntos
Resinas Acrílicas , Quitosana , Mióticos/administração & dosagem , Pilocarpina/administração & dosagem , Resinas Acrílicas/química , Animais , Materiais Biocompatíveis/química , Quitosana/química , Portadores de Fármacos , Feminino , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Masculino , Teste de Materiais , Mióticos/farmacocinética , Peso Molecular , Nanopartículas , Soluções Oftálmicas , Tamanho da Partícula , Pilocarpina/farmacocinética , Coelhos , Espectroscopia de Infravermelho com Transformada de Fourier , SuspensõesRESUMO
In the present study, a mixture of ammonium-bicarbonate (NH(4)HCO(3)) and sodium-chloride (NaCl) particles was used as a porogen additive to fabricate highly macroporous biodegradable poly(lactic-co-glycolic acid) (PLGA) scaffolds. A two-step salt-leaching process was performed after the sample had become semisolidified. Compared to the standard solvent-casting/particulate-leaching (SC/PL) technique, the processing time of this approach was significantly shorter: Instead of several days, only half a day was required. In addition, the polymer/salts/solvent mixture can be easily handled and molded into scaffolds of any specific shape-for example, thin sheet, cylindrical, or bone-shaped-for special applications in tissue engineering. Our results demonstrate that these scaffolds have a highly interconnected open-pore structure as well as greater mechanical properties than those made using the standard SC/PL technique. Primary rat osteoblasts seeded into the scaffolds exhibited good seeding efficiency. The method presented here is a promising approach for fabricating scaffolds for tissue engineering applications.
