The results show the significant value when compared with the standard gel formulation for 0–8 h (Fig. 10). In the stability study, after every 30 days samples were withdrawn and retested for viscosity (cps) and total drug content. The formulation

did not show any significant change in both parameters. It indicates that this formulation was able to retain its stability up to 3 months. Stability data had showed in Table 11. In the present study NLC gel was prepared and characterized for melting point, rheology, SEM, FTIR, DSC, particle size, entrapment efficiency. The melting point was determined by using the melting point determination apparatus to observe the depression in the melting point as result of formation of NLC. The rheological analysis of the formulations showed non-Newtonian type of flow behavior with viscosity in cps changes according to the see more composition of the lipid (Fig. 11). The SEM results revealed that the drug loaded NLC formulations were smooth in surface and uniformly distributed around 0.5 μm in diameter (Fig. 12). The IR spectrum of the drug was recorded and the functional groups were interpreted as per the structure and were found to be appropriate or matching the structure of the drug. In DSC spectrum of formulation the absence of the drug peak (endothermic) shows the no crystalline nature of the drug in the formulation. The Box–Behenken

model design had produced the regression equations for each response (Eqs. (3), (4) and (5)). A positive sign before a factor in polynomial equations represents that the response increases with the factor, while a negative sign means the response and the factors have reciprocal Selleckchem Antidiabetic Compound Library relation. From these equations it could be understand that the particle size in nm (Y1) had positive effect on the lipid composition (X1), while inverse relationship with the stabilizer concentration (X2) and drug–lipid

ratio (X3). The results showed that with increase in the liquid lipid to solid lipid the particle size in nm showed lowering from 350 nm–134 nm. This may be the due to more amount of solid lipids tends to facilitate aggregation of particles. The stabilizer concentration and drug–lipid ratio had a positive effect on the response like Y2 (Entrapment Efficiency %). The entrapment efficiency was found to vary from 77 to 99.22%. The amount of drug released (Y3) (diffused in vitro in 12 h.) was observed to be positive however effect on lipid composition (X1), drug–lipid ratio (X3) and had moderate effect on stabilizer concentration (X2). It was also observed that the observed and predicted values were comparable and the R2 values, Adequate precision values and Model F-Values for the responses, suggests the statistical validity and significance of the equations for the optimization of the formulation. The 3D response surface plots were obtained by varying magnitudes of stabilizer concentration and lipid composition was studied by keeping drug–lipid ratio constant (Fig. 5, Fig.