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Copyright @ Pol J Cosmetol
Pol J Cosmetol 2006, 9(4): 250-263pl,en  The assessment of physical and chemical properties of oxyethylated derivatives of cholesterol in the aspect of micellar solubilisation of lipophilic medicinal productsMichał K. Kołodziejczyk, Marian M. Zgoda Zakład Technologii Postaci Leku Katedra Farmacji Stosowanej Uniwersytetu Medycznego w Łodzi Summary Aim. Solubilising properties of a new group of non-ionic surfactants, formed in the process of cholesterol oxyethylation (homological serieses: n=10, 20, 30, 40), have been assessed. Material and methods. Two homological serieses cholesterol oxyethylates and Fibric acid derivatives: bezafibrate, fenofibrate, gemfibrozil. Basic pre-formulary tests of oxyethylated cholesterol derivatives were begun from the measurements of surface activity their water solutions at the phase boundary. The determination of cmc in g/L, and subsequently in mol/dm3 allowed in the course of further tests to determine the value of the thermodynamic potential of micelle formation ΔGm0. On grounds of calculated values of surface tension within the critical area (σcmc), the Am coefficient was calculated; this coefficient determines the value of the uplift of the lipophilic core at the phase boundary. Results and discussion. Basic physical and chemical parameters, which characterize micellar solutions of oxyethylates and their adducts with fibrates, reveal a specific symmetry of both homological serieses, obtained by the use of either the K-4 catalyst or NaOH. The results from the presented documentation that solubility of a medicinal product increases along with an increase in concentration of oxyethylated cholesterol regardless of the content of segments (CH2CH2O). Thus, what about constant dispersion? Maximum progression of fibrates solubility was achieved for gemfibrozil. Solubilisation efficacy of the remaining derivatives is far lower, without expected correlation to the type of surfactant and its structure. Conclusions. The series of non-ionic surfactants under investigation - products of cholesterol oxyethylating - may be used as potential emulsifiers and solubilisers of lipophilic medicinal products in variant pharmaceutical and cosmetical forms. Key words: solubilization, nonionic tensides, cmc, cholesterol, fibrates |