Fig. 2.

Changes in particle sizes of O/W emulsions made of horse oil and formulated with HLB 10 to 14 and surfactant concentration at 15 and 20% during the storage of 0, 5, 10, and 15 days at 40 °C in the dark. Each value is expressed as mean ± standard deviation of triplicate determination. Values with the different lowercase letters (a–i) within the storage day and values with the different uppercase letters (A–D) within the O/W emulsion formulation are significantly different by Duncan’s multiple range test (p < 0.05)