Positive coefficients of C& A2 in equation (3) indicate the synergistic effect on % drug loading, while negative coefficients of A, B, AB, BC, AC, B2& C2 indicate the antagonistic effect on % drug loading. The “Pred R Squared” of

0.9709 is in reasonable agreement with the “Adj R-Squared” of 0.9945, indicating the adequacy of the model to predict the response of drug loading. The ‘Adeq Precision’ of 57.304 indicated an adequate signal. Therefore, this model is used to navigate PLX3397 manufacturer the design space. The 3-D surface plots for % drug loading are shown in Fig. 3. The effect of drug to lipid ratio on % drug loading is concentration dependent. A decrease in % drug loading from 25.82 (H7) to 16.11 (H8) was observed on increasing E7080 in vivo the drug to lipid ratio from 1:2 to 1:4 (Table 2) while stirring speed also have positive effect on % drug loading. Four formulations (OH1–OH4) were selected from point prediction software of design expert and their responses i.e. particle size, entrapment efficiency and drug loading were evaluated. The composition of all optimum check point formulations, their actual and predicted values for the responses and the % prediction error are shown in Table 4. The low value of % prediction error assures the validity of generated equations and thus depicts

the domain of applicability of RSM model. Finally, the optimum values of ADP ribosylation factor drug to lipid ratio 1:2, surfactant concentration 1.625% w/v and stirring speed 3000 were selected. The optimized formulation (OH4) was further optimized by varying stirring time from 2 h to 2.5 h while maintaining all factors constant. A further decrease in particle size from 140.49 nm (OH4) to 115.1 nm (OPH) was observed on

increasing the stirring time from 2 to 2.5 h while % drug entrapment and % drug loading were not significantly affected (Table 5). A particle size, size distribution & zeta potential curve of optimized formulation (OPH) are shown in Fig. 4 and Fig. 5 respectively. The average particle size, PDI and zeta potential were found to be115.1 nm, 0.409 and −16.7 mV respectively. The entrapment efficiency and drug loading of optimized formulation (OPH) were found to be 71.56% and 26.35% respectively. The Morphology of optimized SLNs was roughly spherical in shape (Fig. 6). In this study, the haloperidol loaded SLNs were designed and prepared by the solvent emulsification diffusion technique. The SLNs were optimized using the 3-level 3-factor Box–Behnken statistical design. The optimized formulation (OPH) exhibited particle size115.1 nm, entrapment efficiency 71. 56% and drug loading 26.35%. The Morphology of optimized SLNs was roughly spherical in shape. All authors have none to declare. The authors express their gratitude to Vamsi labs ltd. Solapur, Maharashtra, India for providing gift sample Haloperidol.