Preparation and physicochemical characterization of ketoprofen-loaded emulsions

The objective of this study was to prepare ketoprofen-loaded emulsions. The emulsions were formulated by mixing soybean oil, surfactants (a mixture of Tween 20 and Tween 80), and distilled water. To determine the most suitable composition for the emulsions, a phase diagram was drawn, representing a mixture of soybean oil, surfactants, and distilled water. From the phase diagram, one-phase formulations were selected and the particle sizes of the formulations were compared. The stability of each formulation was confirmed over 4 weeks at 4 °C, by looking for any change in particle size. The effect of dilution on the pH of emulsion formulations was recorded. A soybean oil concentration of 5 % was sufficient to obtain emulsions. The surfactants used were a mixture of Tween 20 and Tween 80 in a 1:2 ratio, to ensure high ketoprofen solubility. Three formulations, termed E1, E2, and E3, produced emulsions with relatively small particles. The ketoprofen-loaded E1 formulation resulted in the smallest particles. The three formulations were physically stable for 4 weeks with no significant change in particle size. Dilution with distilled water did not alter the pH of the three emulsion formulations, but did change the conductivity. In conclusion, ketoprofen was solubilized by the emulsion formulation, and then remained stable when maintained at 4 °C; additionally, while the pH was unaltered, the conductivity of the formulation was changed by dilution with distilled water.