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In this work the potential use of silica aerogels and hyperbranched polymers as drug delivery systems (DDS) is investigated and discussed. The first part of this work deals with the investigation of the influence of physicochemical properties of silica aerogels (e.g. density, specific surface area, pore sizes and hydrophobicity) on the adsorption of six poorly water-soluble drugs (profens: ketoprofen, flurbiprofen, and ibuprofen, and non-profens: miconazole, griseofulvin and dithranol) and on their in vitro release. The adsorption of drugs on aerogels takes place from supercritical CO2. It is demonstrated that the release of drugs with low and moderate adsorption on aerogels (griseofulvin, dithranol, ketoprofen, flurbiprofen) is faster than that of crystalline drugs. The reason is the enlarged surface of drugs adsorbed on aerogels, the immediate collapse of aerogels in the dissolution medium and the loss of the crystallinity of drugs. Based on experimental findings, a novel method for dissolution enhancement of these drugs using hydrophilic aerogels as host matrices is suggested. It is shown that the release kinetics of drugs from hydrophilic aerogels can be initially predicted when the adsorption of drugs on aerogels is known. The low or moderate adsorption on silica aerogels implies a very fast release of drugs from drug-aerogel formulations. Therefore, the dissolution rate can be enhanced. If the drugs have a very high affinity to silica aerogels (high adsorption), the slow release kinetic is observed. In the second part of this work, the encapsulation of the model drug, acetaminophen, in hyperbranched polyester (Boltorn H3200), polyesteramides (Hybrane H1690, H1200, H1500) and the in vitro release of the drug from drug-loaded microparticles are discussed. For Boltorn, drug-loaded microparticles prepared by gas antisolvent precipitation (GAS), coacervation, and particles from gas saturated solutions (PGSS) were supplied. Hybrane microparticles were prepared by the solvent method in this work. The influence of encapsulation methods and polymer properties on the release kinetics of the drug is studied. It is shown that hyperbranched polymers can increase or delay the drug release depending on their chemical structure and the encapsulation methods used.