The lipid-based formulations were assessed visually according to the rate of emulsification and the final appearance of the emulsion. Grade I – rapidly forming micro emulsion which is clear or slightly bluish in appearance (<1 min); Grade II – rapid forming, slightly less clear emulsion which has a bluish white appearance (<2 min); Grade III – bright white emulsion which is similar to milk in appearance (<3 min); Grade IV – dull, greyish white emulsion with a slightly oily appearance that is slow to emulsify (>3 min).8 Robustness of SEDDS to dilution BIBW2992 purchase studies was studied by diluting it to 50, 100 and 1000 times with various dissolution media

i.e. water, pH 1.2, 3.0 and 6.8. The diluted samples were stored for 24 h and observed for any sign of phase separation or precipitation. The effect of various dispersion medium and volume on droplet size was investigated in this study.

The selected SEDDS formulations (1 ml) were diluted to 50, 100 and 1000 folds of water, pH 1.2, 3.0 and 6.6. The mean globule size of the formulations was determined using Phase Contrast Microscope (PCM). Three replicate analyses were carried out for each formulation, and data presented as mean ± SD. A series of self emulsifying systems were prepared with varying concentrations of oils (25–70% w/w), surfactants (30–75% w/w), and co-surfactants (0–25% w/w) at room temperature for 72 h for visual observation. Twenty compositions of each group with varying concentrations were prepared

in CT99021 manufacturer this investigation. The best 28 self emulsified formulations (Table 2) were identified from 180 of such formulations based on its preliminary evaluation and ternary phase diagrams (Fig. 1) were constructed.9 In group I, the right blend of high HLB surfactant (Cremophor EL; HLB of 13) and a low HLB co-surfactant (Capmul MCM-C8; HLB of 3.5) were selected to form stable emulsion.10 Also Cremophor EL has been used for several commercially available formulations such as Norvir™ capsules, Retrovir® capsules and Sandimmune® tablets. Formulations C1, C5, C11, and C13 have from showed better emulsification property than others. It is noteworthy that surfactant concentration less than 30% resulted in turbid and crude emulsions. In group II, Isopropyl myristate, Cremophore RH 40 and Tween 80 were used. The choice of surfactant for oral delivery is non-ionic surfactant due to less toxicity and its bioactive effects.11 and 12 Cremophor RH40 (Polyoxy 40 hydrogenated castor oil) was used for improving bioavailability of some drugs.13 Tween 80 has lymphotropic character which is the right choice of co-surfactant for drugs with high first pass metabolic effect. In IP6, IP9, IP17 and IP20, Isopropyl myristate concentration 30–70% and surfactant concentration 30–60% showed better self emulsifying properties.