Low aqueous solubility of fluticasone propionate poses a great challenge in new formulation development and characterization. When conducting in vitro dissolution and permeation studies it is important to ensure that sink conditions are met. Compared to organic cosolvents and surfactants, cyclodextrins offer the advantage of distinct biocompatibility with cell lines, what makes them a suitable choice for solubilization purposes. The aim of this study was to develop a reliable high performance liquid chromatography method for quantification of fluticasone propionate in aqueous solutions containing α- and hydroxypropyl-α-cyclodextrin, as well as to investigate the solubilization potential of these cyclodextrins at conditions defined by requirements of permeability tests on Calu-3 cell lines. In this diploma thesis, a reverse-phase chromatographic method for quantitative analysis of fluticasone propionate was successfully developed. The analysis was carried out with isocratic flow, at constant acetonitrile, methanol and phosphate buffer pH 3.5 ratio within the mobile phase (50:15:35, V/V/V). The injection volume was 50 μl, column temperature 40⁰C and flow rate 1 ml/min. At these conditions, the linearity range was confirmed within drug concentration range of 1 μg/ml to 30 μg/ml (correlation coefficient 0.9998). The limit of detection and quantification were found to be 0.24 μg/ml and 0.74 μg/ml, respectively. Using this method, samples obtained in phase solubility studies of fluticasone propionate with α- and hydroxypropyl-α-cyclodextrin carried out at 37⁰C in Hank's balanced salt solution containing calcium ions (pH 7.4), were successfully analysed. Using α- and hydroxypropyl-α-cyclodextrin at 50 mM concentration, the intrinsic solubility of fluticasone propionate was increased by 19.5 and 27.3 times, respectively. Considering the structural characteristics of cyclodextrins and the drug, as well as the obtained phase solubility diagram profiles, it was concluded that the enhancement in fluticasone propionate's solubility was the product of its entrapment inside cyclodextrin and/or drug/cyclodextrin complex aggregates, through non-inclusion mechanisms. The results obtained showed that the solubilization effect of α- and hydroxypropyl-α-cyclodextrin was not sufficient enough to be applied for in vitro permeation studies of fluticasone propionate using cell models. The results of this study could serve as a basis for further research of other cyclodextrins with better solubilization effect on fluticasone propionate.