Natural microemulsions: Formulation design and skin interaction

Reply: Fibrosis in liver as a predictive marker for hepatitis C virus therapy

“…Therefore, the skin penetration of this model drug seemed to be more extensive and might involve deeper skin layers. Interestingly, the results of the penetration studies are quite different to the ones obtained in previous skin permeation experiments where the highest amounts of the model drugs had permeated from the lecithin‐based microemulsions 1. However, these studies present the first direct comparison of the employed natural surfactants in microemulsions, and further in vivo experiments may be useful to find more definite answers regarding their skin penetration and permeation potential.…”

“…Microemulsions based on natural surfactants such as lecithin, sucrose laurate and APG were prepared as previously described in Schwarz et al1 The mixture containing 50% (w/w) surfactant/isopropanol, 40% (w/w) IPM and 10% (w/w) distilled water resulted in an isoptropic microemulsion for all tested compositions (Table 1). Three percent (w/w) of Fluf or Fluc was incorporated into these microemulsion and stored at room temperature.…”

“…A recently published study dealt with natural microemulsions and demonstrated the possibility to create isotropic systems based exclusively on natural, skin‐compatible and biodegradable surfactants. After incorporating the model drugs flufenamic acid (Fluf) and fluconazole (Fluc) into these systems, a thorough characterisation in terms of skin interaction by ATR–FTIR and skin permeation in a Franz‐type diffusion cell set‐up was performed and confirmed the suitability of these formulations for topical administration 1. However, the skin penetration of the incorporated model drugs from the formulations into the horny layer of the skin is also of major interest.…”

Microemulsion based gel for topical dermal delivery of pseudolaric acid B: In vitro and in vivo evaluation

“…The advantages of ME applied to topical dermal delivery of water insoluble drugs were supposed as follows. First, drugs were solubilized in the oil phase or in the interface between oil and water by surfactants and/or co-surfactants of ME, the thermodynamics activity of drugs was increased by the solubilization and favored its partitioning into the skin (Chen et al, 2006;Delgado-Charro, et al, 1997;Fisher et al, 2013;Santos et al, 2008;Zhao et al, 2014); Second, ME exhibited reversibly overcoming the barrier of stratum corneum and increased the drug permeation into or across the skin (Hathout et al, 2011;Schwarz et al, 2012). In addition, certain ingredients of ME formulation always acted as permeation enhancers (Peltola et al, 2003;Saad et al, 2012).The last but not least, due to the facile scale-up and thermodynamic stability, ME was superior to the other colloidal system such as liposome, niosome, and nanoparticle (Kreilgaard, 2002;Neubert, 2011).…”

Monitoring the Distribution of Surfactants in the Stratum Corneum by Combined ATR-FTIR and Tape-Stripping Experiments

“…Moreover, increased attention to the environment has produced a growing interest in the field of natural surfactants such as APG and sugar esters. These natural nonionic surfactants are appropriate alternatives to conventional synthetic surfactants, not least because of their skin friendliness and high environmental compatibility [8,9,10]. …”