The limited removal of pharmaceuticals under conventional sewage treatments requires improvement of advanced treatment technologies to avoid environmental pollution . One of the possible tertiary treatment is adsorption process, using zeolites as sorbent materials. Previous studies have demonstrated that zeolites are efficient adsorbent materials for water remediation. In the present work, the influence on the adsorption of both zeolite characteristics (i.e. framework type, hydrophobicity index, thermal treatments) and physico-chemical parameters of the drug solutions (i.e. pH, ionic strength) are investigated. In particular the adsorption properties of two different zeolites (i.e. Y and Beta) with respect to drugs belonging to various therapeutic classes, having different molecular dimensions and physico-chemical features, have been considered. Adsorption isotherms and thermogravimetric analysis revealed that the amount of pharmaceuticals embedded inside the zeolite framework is related to lattice structure but it as also strongly influenced by zeolites hydrophobicity and by the thermal treatments. The adsorption capacity of a given materials depends also on the pH, and on the ionization constant of the drug. Finally, X-ray diffraction patterns indicated that the crystal structure is markedly modified by the adsorption of pharmaceuticals, proving that the adsorption of the drugs occurs inside the zeolite channel system. It has been found that drug release from porous materials can be employed for controlled drug delivery systems (i.e. devices that enable for an accurate control the rate at which drug molecules are delivered into the bloodstream). In such application, the adsorbent material plays a crucial role in controlling the release of drugs in the body in order to maintain the concentration within the optimum range, hence to improve the therapeutic efficacy and to reduce toxicity. To evaluate the capability of zeolites in drug delivery application, drug release experiments were carried out. The results demonstrate that zeolites are also promising materials for controlled delivery systems.
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