564 JOURNAL OF COSMETIC SCIENCE o CH3 RC--NHCH2CH2CH2N, -- CH2 ,CHCH2-SO 3 - I CH 3 OH O O RC-NHCH2CH21¾C CH2CH2OH alkyl amidopropyl hydroxysulafine sodium alkylamphoacetate o OH II I RC--NHCH2CH21•ICH2CHCH2SO3Na CH2CH2OH O O RC-NHCH2CH21¾CHONa CH2CH2OCH2COONa sodium alkylamphohydroxypropylsulfonate disodium alkylamphodiaeetate O RC-- NHCH2CH21'jiCH2CH2COONa CH2CH2OH O H O -O-- C CH2CH2 I• i+CH2CH2 C-- ONa R sodium alkylamphopropionate sodium alkyl iminodipropionate O CH 3 O !+H 3 RC--NHCH2CH2CH2i CH2CH2COO- R --NHCH2CH2CO-CH3 CH3 alkylamidopropyl betaine alkylamidopropylamine oxide Figure 3. Structures of selected amphoteric surfactants. Additionally, the concentration of CI- within the average micelie decreases as secondary surfactant is added. When micelies in the stated equilibrium consist entirely of CI-, an increase in the concentration of pure CI- micelies will shift the equilibrium to the left, favoring the formation of solid SCI. However, if one disturbs the system such that the concentration of CI- within micelies decreases, i.e., the micelies are no longer pure, then

SOLUBILIZATION OF SCI 565 •'•(OCH2CH2)wOH RC-- O(CH2CH20)zCH2iH (OCH2CH2)yOH polysorbate20, R=C 11H23 polysorbate 60, R=C17H35 polycorbate 80, R=C17H33 CH2OH ( H OR OH O (•CH2CH2)xO RC--OCH2-HC•CH2 I (OCH2CH2)yOH alkyl polyglucoside fatty acid monoglyceride ethoxylate Figure 4. Structures of selected non-ionic surfactants. more aqueous CI- will incorporate within these micelies, leading to greater SCI solu- bility. Thus the addition of secondary surfactants not only increases the strength of CI- association with micelies, but also the number of aqueous CI- molecules per micelie increases. By introducing these selected surfactants, one can solubilize over 5-10% SCI in a clear deterslye system. The following two examples illustrate some surfactants in such com- positions. Based on the condition of mildness, the first example (Table I) can be used in a gentle facial cleanser and the second (Table II) is suitable for baby cleansing products. Table I Clear Detersive Formula of Selected Anionic Surfactants With 8% SCI INCI name Trade name Percentage (%) Sodium dioctyl sulfosuccinate Mackanate EL © (30% active) 45.00 Sodium cocoyl isethionate Hostapon SCI 85G © or Jordapon CI Prill © 8.0 Sodium cocoamphoacetate Miranol Ultra C 37 © (37% active) 4.0 Cocamide MEA Areidex CME © 1.5 Thickener q.s. Preservatives q.s. Fragrance q.s. D.I. water To 100%