Oral route of drug administration is still the preferred route among patients. One drawback of the oral application of medication, that contains poorly soluble active ingredients, is the inferior bioavailability of active pharmaceutical ingredients. Bioavailability can be increased by formulating lipophilic active ingredients as lipid-based systems. One option is the preparation of dried emulsions. In the thesis dried emulsions with simvastatin were prepared. Process of spray drying was used to obtain the product. In the first part the design of experiments methodology (DOE) together with Minitab software was used to determine the effect of various formulation and process parameters on the properties of spray dried products. Varied input parameters were: percentages of starting emulsion components (oil component percentage, percentage of surfactants, dispersion concentration), spraying nozzle position and spraying pressure. In the second part of experiments the input parameters that yielded the best results for the previously determined product critical attributes were established, i.e. based on analyzed data and mathematical models. These product attributes were: particles median size, span of particles size distribution, average normalized boarder length, maximum filling of the rotating cylinder and the process yield. To determine the values of particles median size and size distribution span we used the laser diffraction method. Rotating cylinder method was used to determine the flow properties of prepared products. Process yields were calculated from the mass balance before and after the process. After the optimized spray drying products were produced, we analyzed the desired properties and compared them with the values that were predicted by the mathematical model. We found out that the experimental values are similar to the predicted ones. Considering the results we can say that established models are capable of predicting the output values of particles median size, size distribution span, average normalized boarder length, maximum filling ratio and process yield based on the input process and formulation parameters. Also, based on the flow properties data analysis, we concluded that finished products have poor flow properties and would require additional technological processes (e.g. granulation, adding lubricants etc.) to render them usable for pharmaceutical industry applications. With the utilization of dissolution tests we managed to demonstrate that the release of simvastatin is substantially faster and complete in comparison with the pure simvastatin and the release of simvastatin from the generic tablet.
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