AMINE OXIDES 51 Table VI Combing Behavior of Hair Treated With Shampoo Containing Amine Oxides Wet comb Dry comb Strokes to Formulation Untangle Drag Flyaway (cm) Appearance Feel A 20 + Moderate 4.6 Frizzy Coarse B 8 Slight 4.0 Nearly straight Soft C 20 Moderate 2.3 Curl retained Sticky D 10 Moderate 2.5 Curl retained Soft (10) as a simple means of comparison rather than actual shampoo performance evalua- tion. In general, all the foams generated in this study were of a small cell variety. Shampoo D, containing 2% SDMAO, foamed more than did shampoo formulation C, containing 2% DDMAO. At a level of 0.5% DDMAO in shampoo B, foaming charac- teristics of formulations B and D were similar, though. Interaction of the anionic com- ponent with calcium ions did not alter the relative effects of the two amine oxides. Thus, DDMAO might be expected to suppress foam to a greater extent than SDMAO in a conditioning shampoo formulation. Table VII compares the foam stability of shampoos containing each amine oxide in the presence of artificial soil (olive oil). Formulations containing 2% of either amine oxide (formulations C and D) retained only 40% of their initial foam at a shampoo concentra- tion of 0.10% or less. Formulation B (0.5 % DDMAO) retained 95 % of its initial foam at 0.10% usage. In summary, the differences in the physical properties of DDMAO and SDMAO are reflected in the activity of these compounds in a general shampoo formulation. A shampoo containing DDMAO had untangling and soil tolerance activity which were judged superior to a shampoo containing SDMAO near neutral pH. However, the lack 160 140 - 120 -- 100 - 80- 60- 40 . 20- 0 0.00 - •'•" ' • •'ampoo C .•..I ß shampoo B i • •&___---- •& • shampoo D 0.02 0.04 0.06 0.08 O. 10 CONC. OF FORMULATION (Wl•) Figure 6. Foam height (T = 0 min). 50 ppm CaCO 3 in water. 0.12

52 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 160 140 -- -- 120 - -- 100 - -- 80--- 60 - 40 - 20 - 0 0.00 / m• c B /' D I I I I 0.02 0.04 0.06 0.08 CONC. OF FORMULATION I 0.10 0.12 Figure 7. Foam height (T --- 5 min). 50 ppm CaCO 3 in water. of solubility of DDMAO under acidic conditions prevented a comparison at acidic pH. Furthermore, DDMAO was judged to suppress foam to a greater extent than SDMAO under the test conditions. AMINE OXIDE SOLUTION RINSES A comparison of DDMAO with SDMAO was made using simple solutions of these amine oxides in water or alcohol. Stearalkonium chloride was also included in this evaluation. Due to the total insolubility of DDMAO under acidic conditions, the role of pH was not examined. The effects of co-conditioner ingredients like long-chain alcohols or silicones were also not examined. 160 140 - F 0 A 120 - 100 - H E I 80 - G H T 60 - 40 - 20 - 0 ...•' •'o-- poo c /,.m- A/' ß shampoo B m •'" • ß shampoo D /•, I I I I I 0.00 0.02 0.04 0.06 0,08 0.10 COliC. OF FORIdULATION Figure 8. Foam height (T = 0 min). 150 ppm CaCO 3 in water. 0.12