title: Novel amorphous microporous silica spheres for controlled release applications.
abstract: A new synthesis route for large spherical particles of amorphous microporous silica (AMS) was developed. These novel spherical porous particles with diameter of around 100 µm and pore diameter smaller than 2 nm were prepared using an oil drop method. Molten ibuprofen was successfully loaded into the AMS pores. In vitro release experiments revealed that ibuprofen was released from the spheres via a slow pore diffusion process lasting up to 14 days. Experimentally determined diffusion coefficients of ibuprofen in the porous spheres were of the order of 10(-15) -10(-16) m(2) s(-1) . The present findings reveal the potential of AMS spheres for controlled release of small drug molecules over long time periods. The spherical shape of the AMS particles is advantageous in formulation processes as it provides adequate powder flow properties and reliable release profiles.
authors.affiliation: Centre for Surface Chemistry and Catalysis, K.U. Leuven, Kasteelpark Arenberg, Leuven, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Verraedt
authors.forename: Guy
authors.initials: G
authors.lastname: Van den Mooter
authors.forename: Johan A
authors.initials: JA
authors.lastname: Martens
mesh_terms: D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004058:Diffusion; D004337:Drug Carriers; D007052:Ibuprofen / Q000737:chemistry*; D007700:Kinetics; D008863:Microspheres; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D012995:Solubility; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D012822:Silicon Dioxide; D007052:Ibuprofen