Topical Delivery of Corticosteroids Loaded Nanostructured Lipid Carrier for the Therapy of Eczema

Corticosteroids loaded Nanostructured lipid carrier (NLC)-based gels were successfully developed as a potential topical delivery system for two cortiocosteroidal active pharmaceutical moieties viz. clobetasol propionate (CP) and betamethasone valerate (BV) for the treatment of eczema. Both drugs and their potential excipients for NLC were screened by preformulation studies viz. organoleptic evaluation, melting point analysis, UV-Visible spectra, solubility studies, partition coefficient analysis, Fourier transform-Infrared (FT-IR) analysis, and Differential Scanning calorimetric (DSC) analysis. After the successful characterization of the drug, formulation development was carried out for the selection and optimization of solid lipid, liquid lipid, solid lipid to liquid lipid ratio, surfactant, and co-surfactant concentration, formulation technique, process parameters viz. stirring speed, stirring time and homogenization cycles. After obtaining optimized process parameters, the formulation table for both drugs was generated and NLC was formulated accordingly. The characterizations of the prepared NLC formulations were assessed by means of shape and surface 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 CPNLC formulation encompasses a particle size of 137.9 nm with -20.5mV zeta potential and 0.224 polydispersity index (PDI) which indicates good stability of NLC dispersion. Whereas, BVNLC revealed a particle size of 132.9 nm with - 16.7mV zeta potential and 0.258 PDI. CPNLC formulation showed a good entrapment efficiency of 78.5 % 0.03 with cumulative in vitro release of 85.42 % up to 24 h and BVNLC showed entrapment efficiency of 76.48% with cumulative in vitro release of 83.32% upto 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. The in vivo anti-inflammatory studies were carried out by carrageenan-induced paw edema on male Wistar rats. The results of the anti-inflammatory activity of NLC gel showed a rapid onset of action, as well as a prolonged duration of action as compared with the marketed gel. On the whole, corticosteroids-loaded NLC-based gel formulations were developed but there was a slight difference between the percent inhibition and enhancement ratio results of CPNLC-based gel and BVNLC-based gel. CPNLCG showed the percent inhibition and enhancement ratio as compared to BVNLC. This might be due to the difference between the relative potencies of both drugs. CP has been marked to be more potent as compared to BV, thus, CPNLC-based gel formulations are comparatively superior to BVNLC gel formulations.