Due to their high interfacial area and capability of loading hydrophobic, hydrophilic and amphiphilic drugs, self-assembled nanoparticles are the subject of much attention in view of an application of these dispersions as carrier systems for a variety of different active ingredients. Therefore, the effect of the internal nanostructure of oil-loaded monoglyceride-based nanoparticles on the dermal delivery of diclofenac sodium was investigated. The different self-assembled phases of the nanostructured aqueous dispersions were characterized by small angle X-ray scattering (SAXS). The influence of the different phases ranging from cubic-bicontinuous, over hexagonal and cubic-micellar phases to emulsified microemulsions on the dermal delivery of the incorporated active was examined by Franz-type diffusion cell and in vitro tape stripping experiments on porcine skin. These studies revealed a dependency of the skin permeation of diclofenac sodium on the formulation's internal structure, which could be modified by varying the amount of R-(+)-limonene in the oil phase. A superiority of the emulsified microemulsion, possessing the highest amount of R-(+)-limonene, over cubic or hexagonal phases was evidenced in terms of dermal drug delivery.
Keywords: Dermal delivery; Diclofenac sodium; Emulsified microemulsion; R-(+)-Limonene; Self-assembling monoglycerides.
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