Eucalyptus globulus is an aromatic medicinal plant which known for its
1,8-cineole main pharmacological constituent exhibits as natural
analgesic agent. Eucalyptus globulus-loaded micellar nanoparticle was developed via spontaneous emulsification technique and further evaluation for its
analgesic efficacy study, in vivo
analgesic activity assay in rats. The nanoemulsion system containing Eucalyptus-
micelles was optimized at different
surfactant types (
Tween 40, 60 and 80) and concentrations (3.0, 6.0, 9.0, 12.0, 15.0, and 18.0 wt. %). These formulations were characterized by thermodynamically stability, viscosity,
micelles particle size, pH, and morphology structure. The spontaneous emulsification technique offered a greener
micelles formation in nanoemulsion system by slowly titrated of organic phase, containing Eucalyptus globulus (active compound), grape seed oil (carrier oil) and hydrophilic
surfactant into aqueous phase, and continuously stirred for 30 min to form a homogeneity
solution. The characterizations evaluation revealed an optimized formulation with
Tween 40 surfactant type at 9.0 wt. % of
surfactant concentration promoted the most thermodynamic stability, smaller
micelles particle size (d = 17.13 ± 0.035 nm) formed with spherical shape morphological structure, and suitable in viscosity (≈2.3 cP) and pH value (6.57) for transdermal purpose. The in vivo
analgesic activity assay of optimized
emulsion showed that the
transdermal administration of micellar nanoparticle of Eucalyptus globulus on fore and hind limb of rats, possessed the central and peripheral
analgesic effects by prolonged the rats
pain responses towards the heat stimulus after being put on top of hot plate (55 °C), with longest time responses, 40.75 s at 60 min
after treatment administration. Thus, this study demonstrated that micellar nanoparticle of Eucalyptus globulus formed in nanoemulsion system could be promising as an efficient transdermal nanocarrier for the
analgesic therapy alternative.