Enhanced Percutaneous Permeability of Diclofenac Using a New U-Type Dilutable Microemulsion.


Marina Shevachman, Nissim Garti, Arnon Shani, and Amnon C Sintov. 2008. “Enhanced Percutaneous Permeability of Diclofenac Using a New U-Type Dilutable Microemulsion.” Drug Development and Industrial Pharmacy, 34, 4, Pp. 403–412.


Enhanced systemic absorption in vivo and percutaneous penetration in vitro was demonstrated after transdermal administration of diclofenac sodium formulated in U-type microemulsion. Diclofenac sodium was solubilized in a typical four-component system consisting of an oil, polyoxyethylene-10EO-oleyl alc. (Brij 96V) as the surfactant, and 1-hexanol along water diln. line W46 (40 wt. % surfactant and 60 wt. % oil phase before water titrn.). Viscosity and small angle x-ray scattering measurements have evidenced bicontinuous structures within water fractions of 0.25 and 0.5 along the diln. line. Self-diffusion NMR studies showed that drug mols. accumulated in the interfacial film and, to some extent, dissolved in the oil. Relative to a com. macro-emulsion cream (Voltaren Emulgel), microemulsions contg. paraffin oil or iso-Pr myristate increased the in vivo transdermal penetration rate of diclofenac by two order of magnitude, whereas the rat plasma levels were increased by one order of magnitude. The in vitro data obtained from excised rat skin were comparable to the in vivo results, but suffered from discrepancies from the ideal in vivo-in vitro correlation, which might be explained by optimal in vitro conditions of perfusion and hydration. It has also been found that when jojoba oil is formulated as the oil phase in the microemulsion, the penetration rate of the drug decreases significantly. Based on the three-dimensional structure of jojoba oil, the wax is presumed to prevent the drug from being freely diffused into the skin while migrating from the interfacial film into the continuous oil phase. [on SciFinder(R)]
Last updated on 05/27/2020