Effect of oil-in-water submicron emulsion surface charge on oral absorption of a poorly water-soluble drug in rats.

The effect of oil-in-water submicron emulsion (SE) droplet surface charge on absolute bioavailability of a poorly water-soluble drug (griseofulvin, as model drug) after oral administration was studied in conscious rat. Positively, negatively, and neutrally charged SE were designed and characterized (size, polydispersity index, zeta potential, and pH). Three emulsion formulations, whose compositions included 40% oil phase and differed only in the nature of the emulsifying agent, were retained. Only the positively charged SE showed a higher area under the plasma concentration-time curve (AUC(0 --> infinity)) in comparison with the tablet and with the other SE.