Batch and semicontinuous production of l-ascorbyl oleate catalyzed by CALB immobilized onto Purolite® MN102

In vitro assessment of skin permeation properties of enzymatically derived oil-based fatty acid esters of vitamin C

Current topical formulations containing vitamin C face limitations in therapeutic effectiveness due to the skin's selective properties that impede drug deposition. Consequently, the widespread use of toxic and irritating chemical permeation enhancers is common. Hereby, we investigated enzymatically derived fatty acid ascorbyl esters (FAAEs) obtained using natural oils for their skin permeation properties using the Strat-M® skin model in a Franz cell diffusion study. By evaluating various cosmetic formulations without added enhancers, we found that emulgel is most suitable for enhancing the cutaneous and transdermal delivery of FAAEs. Furthermore, medium-chain coconut oil-derived FAAEs exhibited faster diffusion rates compared to sunflower oil-based FAAEs with long-side acyl residues, including the commonly applied ascorbyl palmitate. Experimental data were successfully fitted using the Peppas and Sahlin model, which accounted for a lag phase and the combined effect of Fickian diffusion and polymer relaxation. In the case of long-chain esters, the lag phase was prolonged, and the calculated effective diffusion coefficients (Deff) were lower compared to medium-chain FAAEs. Accordingly, the highest Deff value was observed for ascorbyl caprylate, being even 60 times higher than for ascorbyl palmitate. These results suggest the emerging potential of emulgel with incorporated coconut oil-derived FAAEs for efficiently delivering vitamin C into the skin.

Esters in the Food and Cosmetic Industries: An Overview of the Reactors Used in Their Biocatalytic Synthesis

Esters are versatile compounds with a wide range of applications in various industries due to their unique properties and pleasant aromas. Conventionally, the manufacture of these compounds has relied on the chemical route. Nevertheless, this technique employs high temperatures and inorganic catalysts, resulting in undesired additional steps to purify the final product by removing solvent residues, which decreases environmental sustainability and energy efficiency. In accordance with the principles of "Green Chemistry" and the search for more environmentally friendly methods, a new alternative, the enzymatic route, has been introduced. This technique uses low temperatures and does not require the use of solvents, resulting in more environmentally friendly final products. Despite the large number of studies published on the biocatalytic synthesis of esters, little attention has been paid to the reactors used for it. Therefore, it is convenient to gather the scattered information regarding the type of reactor employed in these synthesis reactions, considering the industrial field in which the process is carried out. A comparison between the performance of the different reactor configurations will allow us to draw the appropriate conclusions regarding their suitability for each specific industrial application. This review addresses, for the first time, the above aspects, which will undoubtedly help with the correct industrial implementation of these processes.