Permeation-enhancing properties of Nepeta cataria var. citriodora dry extract
This paper presents the research on permeation enhancing properties of Nepeta cataria var. citriodora (catnip) dry extract in comparison to oleanolic acid and ursolic acid. Progesterone was chosen as a model substance for permeation test. The hydrogels made of hydroxypropylmethylcellulose with progesterone, enhancers and ethanol were applied in the study. The in vitro progesterone penetration test was based on the method proposed by Fürst, using artificial lipophilic membranes which were made of colloxylin and dodecanol. Statistical analyses showed an increase in penetration of progesterone caused by catnip dry extract in comparison to ursolic acid and blank sample. HPLC assay was applied to study the effect of enhancers on progesterone physicochemical properties. The solubility of progesterone was tested in solvent systems corresponding to liquid phases of gels. The statistical increase in progesterone solubility was observed in the presence of dry extract in comparison to the result from ursolic acid-containing sample. The partition coefficient of progesterone was evaluated by standard procedures. The statistically significant reduction of log P values for progesterone was determined in the presence of catnip dry extract.