SENSORY ANALYSIS OF A CHITOSAN GEL NANOFORMULATION 307 volunteers who did not see differences. Table IV shows the p value obtained comparing the percentage of volunteers who choose the fi rst or the second sample in the pair, for the attributes mentioned above. Only for the attributes immediate stickiness (comparisons CH vs. HEC and CH-NC vs. HEC-NC), fi lm formation (all comparisons), and preference (comparisons CH vs. HEC and CH-NC vs. HEC-NC), the percentage of volunteers who choose one sample in the pair was different from the percentage of volunteers who choose the other sample. The statistically signifi cant results are shown in Figure 4. Table II Responses from the Volunteers, in Percentage, When Comparing the Paired Samples in the Phase I Sensory Study Attribute Percentage of volunteers Paired analysis CH vs. HEC CH-NC vs. HEC-NC CH vs. CH-NC Spreadability Did not see differences 45 48 40 Saw differences 55 52 60 Chose the fi rst sample 13 2 35 Chose the second sample 42 50 25 Oiliness Did not see differences 48 50 35 Saw differences 51 50 65 Chose the fi rst sample 33 37 38 Chose the second sample 18 13 27 Immediate stickiness Did not see differences 42 37 20 Saw differences 69 63 80 Chose the fi rst sample 47 58 33 Chose the second sample 22 5 47 Residual stickiness Did not see differences 45 42 48 Saw differences 55 58 52 Chose the fi rst sample 45 45 17 Chose the second sample 10 13 35 Film formation Did not see differences 28 35 28 Saw differences 72 65 72 Chose the fi rst sample 62 53 22 Chose the second sample 10 12 50 Homogeneity of the fi lm Did not see differences 35 45 22 Saw differences 65 55 78 Chose the fi rst sample 28 20 48 Chose the second sample 37 35 30 Preference Did not see differences 18 27 10 Saw differences 81 73 90 Chose the fi rst sample 13 20 52 Chose the second sample 68 53 38 CH: chitosan gel, HEC: hydroxyethyl cellulose gel, NC: nanocapsules.

JOURNAL OF COSMETIC SCIENCE 308 Concerning the discriminative sensory analysis, it could be seen that there were no sig- nifi cant differences among CH and HEC gels for the attributes spreadability, oiliness, and residual stickiness, demonstrating that the innovative chitosan gel could be used without prejudice on some sensory properties. However, the chitosan hydrogel showed signifi cant higher immediate stickiness and perception of fi lm formation on the skin than the hy- droxyethyl cellulose gel, despite the presence of nanocapsules. The higher stickiness is probably related to the bioadhesive properties of the polymer, and the fi lm formation is widely described in the literature for this polymer (3). It is important to notice that the residual stickiness was not considered higher for the chitosan hydrogels, showing that this effect was temporary, limited to time of application. Table III p Values Obtained from χ2 test for Phase I Sensory Study (Comparison between the Percentage of Volunteers Who Saw Differences with the Percentage of Volunteers Who Did Not See Differences) Attribute p Value CH vs. HEC CH-NC vs. HEC-NC CH vs. CH-NC Spreadability 0.439 Oiliness 0.796 1 0.020* Immediate stickiness 0.005* 0.039* 0.000* Residual stickiness 0.439 0.197 0.796 Film formation 0.001* 0.020* 0.001* Homogeneity of the fi lm 0.020* 0.439 0.000* Preference 0.000* 0.000* 0.000* CH: chitosan gel, HEC: hydroxyethyl cellulose gel, NC: nanocapsules. *Signifi cant difference (p 0.05). Table IV p Values Obtained from χ2 test for Phase I Sensory Study (Comparison between the Percentage of Volunteers Who Chose One or Another Formulation from the Paired Analysis) Attribute p Value CH vs. HEC CH-NC vs. HEC-NC CH vs. CH-NC Spreadability —a —a —a Oiliness —a —a 0.262 Immediate stickiness 0.019* 0.000* 0.248 Residual stickiness —a —a —a Film formation 0.000* 0.000* 0.010* Homogeneity of the fi lm 0.423 —a 0.109 Preference 0.000* 0.003* 0.276 CH: chitosan gel, HEC: hydroxyethyl cellulose gel, NC: nanocapsules. a The test was not applicable since the number of volunteers who saw difference was not statistically higher than the number of volunteers who did not see differences. *Statistical difference (p 0.05).