SLN (Solid Lipid Nanoparticles) are a drug-carrier system suitable for lipid soluble, poorly water soluble or chemically unstable drugs. The positive effect of lipid media on the absorption of drugs from the GIT is meanwhile often reported. An oral administration by using a lipid matrix composed of solid physiological compounds can therefore optimize the drug release by adjustment of the release profile, the absorption rate and the bioavailability of many drugs. Solid Lipid Nanoparticles lead to a high surface for an optimized absorption, provide a protective ''cover'' of incorporated chemically unstable drugs and allow modification of the release profile of drugs during a desired period of time.A model drug was incorporated in a lipid matrix. SLN were produced by high pressure homogenization. Different pressures and numbers of homogenization cycles were applied at various production temperatures. Poloxamers, lecithins, Tagats, Polysorbates and sodium cholate as surfactants and different sugars as cryoprotectants are used in commercial products and accepted by the regulatory authorities for oral use. Therefore they were selected as surfactants or surfactant combinations. After the production in an aqueous medium the SLN were lyophilised. The lyophilisation was optimized by using different concentrations of cryoprotectants and lyophilisation parameters.The particle size of the SLN formulation before lyophilisation and of the lyophilised SLN after redispersion was determined by Photon Correlation Spectroscopy and Laser Diffractometry. The drug loading capacity of the lyophilised SLN and the drug release from the SLN were determined by UV/HPLC - technique.A tablet, a capsule or a sachet for reconstitution as a drinking suspension are possible formulations for the oral administration. Production of SLN containing pellets is also possible.