Transdermal diffusion of enzymatically synthesized oil-derived phloridzin esters from oil in water emulsion

Abstract

Phloridzin is flavonoid known for its antioxidant and UV-protective effects on the skin. However, it has limited solubility in both hydrophilic and lipophilic media, therefore it should be derivatized prior to incorporation in final products. Hereby, we applied lipase-catalyzed acylation to produce different phloridzin ester mixtures using coconut and linseed oil as acyl donors and examined their transdermal delivery. The new derivatives were incorporated in oil in water emulsion to examine their diffusion through artificial skin-mimicking Strat-M® membrane using Franz diffusion cell. The transport of esters was successfully modelled by modified Kosrmeyer-Pepas equation. Lag phase, lasting 90-170 min, was detected for all esters. For coconut oil-derived esters process was entirely controlled by diffusion, while for linseed oil-based esters polymer relaxation was observed, as well. Effective diffusion coefficients of medium-chain esters obtained using coconut oil were one order of magnitude higher compared to long-chain ones. Zeta potential of both formulations was constant during six month storage period, indicating their high stability. Obtained results underscore suitability of natural triglycerides application in the production of phloridzin esters for topical products.