The use of sulfur-containing products for the treatment of the hair and scalp to combat seborrhea dates at least to the first decade of the twentieth century and has continued through the present. In these sulfur-containing preparations, the sulfur generally is colloidal, and has been suspended in aqueous, hydrophilic ointments as well as anhydrous, hydrophobic compositions.
One problem which has remained throughout the long history of the use of sulfur-containing compositions is the fact that sulfur is not soluble in the composition, and even in colloidal size, particles tend to form a separate and distinct phase in the compositions. This separate and distinct phase can take the form of isolated sulfur particles or crystals which are visible throughout the composition and also as a precipitate which settles at or near the bottom of such compositions. The latter situation is particularly disadvantageous because it goes beyond appearance and affects the effectiveness of the product for its intended function. Even if the product is restirred by hand before use, the distribution of sulfur therein is frequently non-uniform, resulting in a non-uniform application of sulfur on the hair or scalp.
Efforts to solve the problem of having two phases in such sulfur-containing compositions have generally failed, with the result being that compositions are made and sold having a cosmetically unattractive two-phase appearance. One attempt to solve the problem associated with two-phase systems has been the use of colloidal sulfur in conjunction with a colloidal co-suspending agent such as gum arabic (acacia). Nevertheless, even though preparations containing colloidal sulfur and acacia disperse readily in water to give milky fluids, on standing such dispersions generally form a precipitate so the dispersions should be freshly prepared for use.