Dermal application of various active substances is widely preferred for topical or systemic
delivery. SLNs consist of biocompatible and non-toxic lipids and have a great potential for topical application
in drugs. In this study, semisolid SLN formulations were successfully prepared by a novel
one-step production method as a topical delivery system of etofenamate, an anti-inflammatory drug.
Compritol 888 ATO and Precirol ATO 5 were chosen as lipid materials for the fabrication of the formulations.
In-vitro evaluation of the formulations was performed in terms of encapsulation efficiency,
particle size, surface charge, thermal behavior, rheological characteristics, in vitro drug release profile, kinetics, mechanisms,
stability, and anti-inflammatory activity. The colloidal size and spherical shape of the particles were proved. According
to the results of the rheological analysis, it was demonstrated that the semisolid SLN formulations have a gel-like
structure. Stability studies showed that semisolid SLNs were stable at 4°C for a six month period. Zero order release was
obtained with Precirol ATO 5, while Compritol 888 ATO followed the square root of time (Higuchi's pattern) dependent
release. Semisolid SLNs showed higher inhibitory activity of COX in comparison with pure etofenamate. In conclusion,
etofenamate-loaded semisolid SLN formulations can be successfully prepared in a novel one-step production method and
useful for topical application.