Abstract: Improved liquid antimicrobial solutions useful as preservative additives to personal care preparations, particularly cosmetic formulations and the like, are provided which comprise 1,3-dimethylol-5,5-disubstituted hydantoin, liquid aromatic alcohol, and iodoalkynyl alkyl carbamate. A preferred antimicrobial solution can be prepared by producing the 1,3,dimethylol-5,5-disubstituted hydantoin in situ in the selected liquid aromatic alcohol and then adding to the resulting solution the previously prepared iodoalkynyl alkyl carbamate. The solutions are surprisingly water dispersible and display broad spectrum antimicrobial effectiveness, particularly antifungal effectiveness, at a relatively low usage concentration in a cosmetic medium.

Abstract: A method of preparing a formaldehyde substituted hydantoin in the form of a liquid antimicrobial preservative solution is disclosed. The inventive solution prepared by the disclosed method comprises a condensation product of a 5,5-disubstituted hydantoin and formaldehyde prepared in the presence of an antimicrobial liquid phenylic or benzylic alcohol. The inventive solution inhibits or retards microbial growth when an effective microbial inhibiting amount is subsequently added to a medium capable of supporting undesirable microbial growth. Preferably the inventive solution contains 1,3-dimethylol-5,5-dimethyl hydantoin prepared in the presence of phenoxyethanol and including an effective antimicrobial amount of at least one paraben preservative prepared by an embodiment of the disclosed method.

Abstract: A method of preparing an antimicrobial preservative system in a substantially anhydrous liquid form is disclosed. The antimicrobial preservative system inhibits or retards microbial growth when an effective antimicrobial amount is subsequently added to a medium capable of supporting undesirable microbial growth. More particularly, the preservative system comprises a condensation product of a 5,5-disubstituted hydantoin and formaldehyde prepared in the presence of a substantially anhydrous, water-miscible, solvent and an alkalizing agent. Also disclosed is a cold-stable, substantially anhydrous liquid preservative system comprising 1,3-dimethylol-5,5-dimethylhydantoin alone or in combination with an effective antimicrobial amount of at least one paraben preservative prepared by an embodiment of the disclosed method.

Abstract: Cationic surfactants are provided which are useful alone as the active compounds in creme hair rinse and in conjunction with anionic surfactants in other hair conditioning preparations based on anionic-cationic surfactant systems. Such cationic surfactants are non-irritating to the eyes and are compatible with the other conventional ingredients used in hair conditioning preparations. These cationic surfactants are also compatible with anionic surfactants without objectionably reducing or otherwise interfering with the foam normally formed by the anionic surfactants in hair conditioning preparations. Useful cationic surfactants of the present invention have the following general formula: ##STR1## wherein ##STR2## is a fatty acid group containing from 6 to 20 carbon atoms, and n.sub.1, n.sub.2 and n.sub.3 are the same or different integers not exceeding 3. Two cationic surfactants of the invention presently preferred are: isostearylamidopropylmorpholine lactate and stearylamidopropylmorpholine lactate.