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Item type:Publication, Access status: without files , Hyperbranched polymers as drug carriers: microencapsulation and release kinetics(Taylor & Francis, 2008-10-07); ; ; ; Publicationtype: Journal Article31 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Aerogels: Tailor-made carriers for immediate and prolonged drug release(Party of Powder Technology (Japan), 2005-01-01); ; The potential of inorganic polymeric materials - silica aerogels - as tailor-made drug carriers is discussed. It is shown that the dissolution rate of poorly soluble drugs can be significantly changed through the adsorption on silica aerogels. Adsorption takes place in supercritical CO2 and allows distribution of the drugs inside the aerogel matrix on the molecular level. The drug concentration in the aerogel is explicitly determined by the temperature, bulk concentration of the drug in the supercritical phase and the properties of the aerogel (density, pore size distribution and surface area). The release rate of the drug depends on the hydrophobicity of the aerogel. In the case of hydrophilic aerogels, an extremely fast release - even compared with nanocrystals - of drugs is achieved, which is especially advantageous for poorly water-soluble drugs. Hydrophobic aerogels exhibit a slower release which is governed by diffusion. In addition, the possibility of generating organic microparticles inside the pores of the aerogels by precipitation from supercritical solutions is discussed.Publicationtype: Journal Article36 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Dissolution rate enhancement by adsorption of poorly soluble drugs on hydrophilic silica aerogels(Taylor & Francis, 2004-01-11); ; ; The aim of this work is to evaluate the feasibility of hydrophilic silica aerogels as drug carriers and to investigate the influence of the aerogels properties on the release rate of poorly water-soluble drugs. Hydrophilic silica aerogels of different densities were loaded with two model drugs, ketoprofen and griseofulvin, by adsorption from their solution in supercritical CO 2. It is demonstrated that up to 30 wt% of ketoprofen and 5.4 wt% of griseofulvin can be deposited on hydrophilic aerogels through physical adsorption. The obtained drug-aerogel formulations were characterized by IR- and UV-spectroscopy, X-ray diffraction and scanning electron microscopy. Release kinetics of both drugs were studied in vitro. The release rate of ketoprofen from the drug-aerogel formulation is much faster than that of the corresponding crystalline drugs. The release rate of ketoprofen increases in 500% and that of griseofulvin in 450%, respectively. The reasons for the release enhancement are the enlarged specific surface area of drugs by adsorption on aerogels compared to their crystalline form and the immediate collapse of aerogel network in aqueous media. The dissolution rate of poorly water soluble drugs can be significantly enhanced by adsorption on highly porous hydrophilic silica aerogels.Publicationtype: Journal ArticleScopus© Citations 116 29 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Feasibility study of hydrophilic and hydrophobic silica aerogels as drug delivery systemsThe feasibility of silica aerogels as oral drug delivery systems was investigated. Silica aerogels were loaded with several drugs by adsorption from their solutions in supercritical CO2. It was demonstrated that for all three drugs investigated here, high loading of the aerogel could be achieved. The loaded aerogels were characterized by IR- and UV spectroscopy and X-ray diffraction in order to show that no degradation of the drugs occurred during the loading procedure. The release profiles of two drugs (ketoprofen and griseofulvin) from loaded aerogels were measured. It was found that the drugs adsorbed on hydrophilic silica aerogels dissolve faster than the corresponding crystalline drugs. This fact can be explained by both an increase in the specific surface area of the drug adsorbed on the aerogel and its non-crystallinity in this state. The influence of density and hydrophobicity of aerogels on both the adsorption and release of drugs were studied.Publicationtype: Journal Article28