Nanostructured lipid carriers (NLC) based controlled release topical gel of clobetasol propionate: design and in vivo characterization

Nanostructured lipid carrier (NLC)-based gel was developed as a potential topical system for clobetasol propionate (CP) topical delivery for the treatment of eczema. The characterizations of the prepared NLC formulation for topical application on the skin were assessed by means of morphology (SEM), particle size distribution, zeta potential analysis, drug entrapment efficiency, and in vitro drug release studies to select the optimized NLC formulation. The optimized NLC formulation encompasses particle size of 137.9 nm with -20.5mVzeta potential and 0.224 polydispersity index which indicates good stability of NLC dispersion. NLC formulation showed a good entrapment efficiency of 78.5 %+/- 0.03 with cumulative in vitro release 85.42 % up to 24 h. The optimized NLC formulation was suitably gelled and characterized for rheology, drug content, ex vivo drug permeation studies, and drug release kinetics studies. The permeation study revealed that the permeability parameters like steady-state flux (Jss), permeability coefficient (Kp), and enhancement ratio were significantly higher for NLC-based gel formulation as compared to marketed formulation of clobetasol propionate. The value of r(2) (Korsmeyer-Peppas equation) indicated good linearity showing anomalous (non-Fickian) diffusion viz. drug release is controlled by more than one process, i.e., superposition of both phenomenon, the diffusion controlled as well as swelling controlled release. The anti-inflammatory activity of NLC gel via paw oedema technique showed a rapid onset of action, as well as a prolonged duration of action as compared with the marketed gel.