Purpose: We formulated a solid-in-oil nanosuspension (SONS) as a novel transdermal delivery carrier for diclofenac sodium (DFNa). The basic transdermal characteristics of the SONS were evaluated using a Yucatan micropig (YMP) skin model.
Methods: DFNa-sucrose erucate (i.e. surfactant) complexes were prepared via the formation of a water-in-oil emulsion. The complexes were suspended in isopropyl myristate (IPM) to form a SONS. The basic transdermal characteristics of the SONS were examined using full-thickness YMP dorsal skin in a Franz-type diffusion cell. DFNa powder suspended in IPM without complex formation was used as a control. The effect of the weight ratio of surfactant to DFNa on DFNa penetration of the skin was evaluated.
Results: DFNa was successfully dispersed into IPM as a nanosized suspension via complex formation with sucrose erucate. The resultant SONS increased the permeability flux of DFNa across the YMP skin by up to 3.8-fold compared with the control. The size of the SONS depended on the weight ratio of the surfactant to DFNa. The optimal weight ratio for the highest DFNa permeation was 8.8, at which point the mean diameter of the SONS was 14.4 nm.
Conclusion: The SONS formulation can enhance the percutaneous absorption of DFNa.