EMULGEL FORMULATION AND IN VITRO AND IN VIVO ASSESSMENT 11 spread at the graph—the fi rst one spreads through the highest point (R0) and the second one spreads through the infl exion point, that is, the point in time at which the recovery curve deviates from its initial linearity. At this point, QE and QR are divided (Figure 5). The Q-parameters include the following parameters (see Figures 6 and 7): 1. Q0 = The maximum recovery area, that is, the area under the highest point (R0). 2. QE = The elastic recovery area of the skin. 3. QV = The viscous recovery area of the skin. The parameters calculated by Cutometer Software include the following: 1. Q0 = Q0 the maximum recovery area, that is, the area under the highest point (R0). 2. Q1 = QE/Q0 the elastic recovery of the skin. 3. Q2 = Q2 = QV/Q0 the viscous recovery of the skin. 4. Q3 = (QE + QV)/Q0 the total viscoelastic recovery of the skin, that is, overall skin elasticity. R-PARAMETERS The following additional parameters are calculated by software: 1. R1 = Uf–Ua, the residual deformation at the end of the fi rst measuring cycle (resilient distension). 2. R2 = Ua/Uf, the ratio of total retraction to total deformation, which is called gross elasticity of the skin (viscous deformation). Figure 4. Organoleptic characteristics of two studied emulgel formulations.

JOURNAL OF COSMETIC SCIENCE 12 3. R3 = Last maximum amplitude (last maximal deformation). 4. R4 = Last minimum amplitude (last residual deformation). 5. R5 = Ur/Ue, net elasticity without viscous deformation. 6. R6 = Uv/Ue, the ratio between delayed and immediate deformation, which indicates the relative contributions of the viscoelastic plus viscous and the elastic distension to the total deformation (viscoelastic ratio, the ratio of viscoelastic to elastic distension). 7. R7 = Ur/Uf, the ratio of immediate retraction to the total deformation, which is called biological elasticity (the ratio of immediate retraction to total distension). 8. R8 = Ua, the fi nal retraction after removal of the vacuum (total recovery of the skin). 9. R9 = R3–R0, the difference in maximal skin deformation between the last and the fi rst suction called hysteresis (H). LIMITATIONS OF THE STUDY The current study has two main limitations. First, the number of volunteers who used the emulgel was relatively small. However, this experimental step allowed gathering relevant data on the effi cacy and the sensorial effects of the emulgel prepared and used in this study. Second, we did not compare the effi cacy and the sensorial effects of the emulgel with those of the gel and the emulsion components used to prepare the emul- gel separately. Table VII Results of Paired Sample T-Test Analysis Property Mean N p-value Moisturization of LG emulgel 4.0714 42 0.198 Moisturization of blank emulgel 3.8810 42 Cooling effect of LG emulgel 3.7143 42 0.0001 Cooling effect of blank emulgel 2.7381 42 Emollience of LG emulgel 4.0952 42 0.063 Emollience of blank emulgel 3.8095 42 Odor of LG emulgel 4.1905 42 0.0001 Odor of blank emulgel 1.7143 42 Smoothness of LG emulgel 4.1667 42 0.006 Smoothness of blank emulgel 3.7857 42 Absorbance of LG emulgel 4.0952 42 0.653 Absorbance of blank emulgel 4.0238 42 Compatibility of LG emulgel 4.0238 42 0.230 Compatibility of blank emulgel 3.7857 42 Astringent effect of LG emulgel 2.4286 42 0.254 Astringent effect of blank emulgel 2.1667 42 Overall evaluation of LG emulgel 3.9286 42 0.0001 Overall evaluation of blank emulgel 3.4286 42 Free sample of LG emulgel 1.1190 42 0.0001 Free sample of blank emulgel 1.4762 42 Ready-to-buy LG emulgel 1.0952 42 0.005 Ready-to-buy blank emulgel 1.3095 42