resumo
The possibility of tailoring apatite granules as a controlled release system for the drug model 5-Fluorouracil (5FU) has been examined. Apatite granules (SDG) were obtained by spray drying suspensions of hydroxyapatite (HAP) nanoparticles previously precipitated from citrate solutions [M.A. Martins, C. Santos, M.E.V. Costa, M.M. Almeida, Preparation of porous hydroxyapatite particles to be used as drug delivery systems, Advanced Materials Forum 11 (455) (2004) 353-357]. SDG had donut shape and very high specific surface area (150 m(2)/g) indicative of high porosity. SDG were. poorly crystalline HAP but turned into biphasic granules (HSDG) with crystalline tricalcium phosphate and HAP after annealing at 800 degrees C, while reducing their surface area down to similar to 6 m(2)/g. SDG and HSDG were soaked in a 5FU solution at pH 5.2 and room temperature during several days and then transferred to a phosphate buffered solution (PBS) at pH 7.4 and 37 degrees C, for releasing 5FU. The comparison between the 5FU adsorbing and releasing behaviours exhibited by SDG and HSDG shows that engineering the granules characteristics, i.e. specific surface area, surface chemical composition, porosity and crystal phase composition allows the 5FU release profile to be controlled. (C) 2008 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
palavras-chave
BETA-TRICALCIUM PHOSPHATE; HYDROXYAPATITE PARTICLES; DRUG-DELIVERY; MICROSPHERES; CELLS; NANOPARTICLES; BIOCERAMICS; BONE; FABRICATION; COMPOSITE
categoria
Materials Science
autores
Santos, C; Martins, MA; Franke, RP; Almeida, MM; Costa, MEV
nossos autores
Manuel António Martins da Silva
Investigador
Maria Elisabete Jorge Vieira Costa
Colaborador
Maria Margarida Tavares Lopes Almeida
Professor(a) Jubilado(a)Grupos
G1 - Materiais Porosos e Nanossistemas
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
This work was supported in part by the European Project G5RD-CT2000-00282 Tissue Reactor.