USE OF LECYTHIS PISONIS OIL IN COSMETIC CREAMS 247 It is possible to infer that after the stability test, the viscosity of the cream decreased, and the same occurred when the oil concentration was increased in the formulation (Table III). The viscosity of an emulsion could be altered by changing the lipid composition, propor- tions of the aqueous and oil phases, concentrations of viscosity donors and emulsifi ers, and by the presence of polymers (30). Therefore, the viscosity of the oil and of the formulation are interrelated, as the viscosity increases with the ester chain length of fatty acids in the oil and decreases with the level of unsaturation (31). The changes in viscosity affected the spreadability of most of the samples (Table III). The higher the fatty acid content, the lower the thermal stability of the formulation (32). The samples exhibited similar spreadability before the stability test, and it increased with the oil concentration in the cream. F2 presented the best spreadability. Table IV presents the fatty acid concentrations in all samples and, notably, the base cream used already contained fatty acids that added to the fatty acids in the formulations. In addition, the fatty acid composition of the oil did not change during the stability test, as shown in Table IV. Comparing F0 before and after the stability test, it can be observed that the amount of myristic and palmitic acids did not change. Oleic, linoleic, and pal- mitic acids were the main constituents of the oil and remain the major fatty acids in the creams, expect in F1AST. There were no changes in the quantity of the compounds when comparing the formulations before and after the stability test. The variation in stability may be related to interactions among the cream components and the oil because the oil itself was stable during the test. However, no differences in the cream formulation before and after the stability test were observed. Although most fatty acids are stable until 300°C, they could change during storage for long periods, being damaged by oxidation or hydrolytic processes (33). That is why sta- bility tests of cosmetics products are important to avoid compromising the health of consumers and ensure a good product. At time 0 of the challenge test, before the stability test, all samples presented contamina- tion, as expected, and supported growth of E. coli, S. aureus, P. aeruginosa, C. albicans, and A. niger. After 7 d, there was minimal growth of S. aureus and A. niger. However, after 28 d, no microbiological growth was detected for all microorganisms tested, showing the effi - cacy of the preservatives in the base. At time 0 of the experiment performed after the stability test, all samples were positive for contamination. After 28 d, no microbiological growth was detected. Therefore, it is possible to infer that the preservative system was effective, in compliance with the regulatory standards described in RDC 481/99 (18). CONCLUSION So, the developed L. pisonis oil cream fulfi lled all the requirements of ANVISA, including satisfactory organoleptic and physical–chemical parameters, including the preservative system that is widely used in formulations. The parameters of the 10% oil formulation considerably differed from the other formulations. The viscosity of the cream decreased with an increasing oil concentration, affecting the spreadability. Although no signifi cant changes in the formulation pH could be detected, it is recommended to use a stabilizer to assure a stable pH (5.5–6.5).

T able IV Relative Concentrations of Fatty Acids in the Cream Formulations before and after the Stability Test Formulation FAME (%) OilBST OilAST F0BST F0AST F1BST F1AST F2BST F2AST F3BST F3AST Myristic (C14:0) 0.09 ± 0.1 0.08 ± 0.04 3.36 ± 0.58 3.55 ± 0.37 1.80 ± 0.32 2.61 ± 0.09 0.39 ± 0.04 0.91 ± 0.01 0.35 ± 0.01 0.70 ± 0.03 Palmitic (C16:0) 12.20 ± 0.01 11.96 ± 0.06 65.89 ± 0.46 46.05 ± 1.01 35.09 ± 0.14 49.34 ± 0.23 16.95 ± 0.11 28.69 ± 0.20 19.28 ± 0.2723.25 ± 0.31 Palmitoleic (C16:1 n-7) 0.41 ± 0.02 0.31 ± 0.04 — — — — — — — 0.25 ± 0.07 Stearic (C18:0) 6.99 ± 0.03 7.15 ± 0.01 24.47 ± 0.54 18.21 ± 0.67 13.49 ± 0.40 22.93 ± 0.89 8.66 ± 0.03 15.48 ± 0.14 9.95 ± 0.2612.45 ± 0.11 Oleic (C18:1 n-9) 49.95 ± 0.02 38.24 ± 0.03 2.29 ± 0.17 15.00 ± 0.51 42.27 ± 0.07 9.40 ± 0.90 47.38 ± 0.11 38.84 ± 0.27 48.46 ± 0.67 41.92 ± 0.22 Linoleic (C18:2 n-6) 29.84 ± 0.01 41.67 ± 0.02 2.90 ± 0.27 7.21 ± 0.80 7.36 ± 0.18 4.55 ± 0.44 24.65 ± 0.01 11.78 ± 0.07 31.62 ± 0.43 18.10 ± 0.04 Linolenic (C18:3 n-3) 0.2 ± 0.03 0.20 ± 0.02 — — — — 0.50 ± 0.06 — — — Arachidic (C20:0) 0.18 ± 0.01 0.18 ± 0.03 — 1.75 ± 0.13 — 1.44 ± 0.40 0.16 ± 0.04 0.35 ± 0.01 0.14 ± 0.06 — C20:1 n-9 0.07 ± 0.01 0.09 ± 0.01 — — — 0.90 ± 0.02 0.69 ± 0.06 3.44 ± 0.11 0.91 ± 0.05 2.94 ± 0.26 Behenic (C22:0) 0.05 ± 0.01 0.12 ± 0.01 — 6.73 ± 0.46 — 4.74 ± 1.10 0.62 ± 0.03 — — — BST: before stability test AST: after stability test. JOURNAL OF COSMETIC SCIENCE 248