J. soc. cos. CHEM. 15, 303--310 (1964) DETERMINATION OF ALLANTOIN AND THE ALUMINUM ALLANTOINATES IN VARIOUS COSMETIC AND PHARMACEUTICAL PREPARATIONS By SIDNEY A. K^TZ, Ph.D.,* RICHARD TURSR, PI•.D.,• and S. B. MEee^, B.S.{ ABSTRACT Procedures for the colorimetric determination of allantoin involv- ing removal of interfering substances by chloroform extraction have been developed. Their use for the determination of allantoin in a variety of cosmetic preparations is described. INTRODUCTION Because of their reported (1) therapeutic properties, allantoin and the aluminum allantoinates have been incorporated into various cosmetic preparations such as skin creams, lotions, lipsticks, and shaving prepara- tions. With the increasing use of allantoin in these products, suitable methods for the determination of allantoin and its aluminum derivatives are needed for quality control and product stability studies. Although the assay methods issued by the Board of Standards of the Toilet Goods Association (2) are well suited to the evaluation of the purity of allantoin, they are of little value in the determination of allantoin in complex cos- metic and pharmaceutical preparations because this method lacks speci- ficity. Interferences by antiseptics, antibiotics, quarternaries, lanolin derivatives and stearates lead to inaccurate results. Likewise, the color- imetric procedures of Young and Conway (3) and of E1 Ridi, Magd, and E1 Marsy (4) cannot be used directly. The colorimetric procedure of Domhas (5) is not applicable to the determination of allantoin in cosmetic and pharmaceutical preparations unless extensive separation and puri- fication techniques are employed. The chromatographic procedure of * Chemistry Dept., Rutgers University, Camden 2, N.J. • Pharmaceutical Labs. Div., Colgate-Palmolive Co., New Brunswick, N.J. $ Schuylkill Chemical Co., Philadelphia 32, Pa. 303

304 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Deshusses and Desbaumes (6) is applicable to the determination of al- lantoin in these preparations, but the procedure is somewhat time consum- ing. The procedures described in this report offer the advantages of speed, simplicity, and wide scope. EXPERIMENTAL vt. ztpparatus and Reagents A Beckman Model DU spectrophotometer with 1 cm. cells was used for all spectrophotometric measurements. Atmmoniacal Copper Tartrate Reagent. Dissolve 100 g. of ammonium sulfate in approximately 400 ml. of distilled water and filter into a 1 1. volumetric flask. Add 100 ml. of 10% sodium hydroxide and 12 g. of sodium tartrate. Dissolve 5 g. of cuptic sulfate in distilled water and add this solution to the flask. Dilute the contents of the flask to the mark with distilled water and mix well. This reagent will not give a blank for months if it is stored in a well-filled, tightly stoppered, amber glass bottle. Folin ztcid Molybdate Reagent. Prepare a stock solution of 30% bro- minated sodium molybdate by dissolving 3C0 g. of sodium molybdate in distilled water and diluting to 1 1. Add 2-3 drops of liquid bromine and allow the solution to stand overnight. Transfer 500 ml. of the clear supernatant liquid to a 1 1. volumetric flask and add 225 ml. of 85% phosphoric acid while stirring. Add 150 ml. of cold 25% v/v sulfuric acid while stirring, and place the flask on a hot water bath in a hood for 15 min- utes to remove excess bromine, as indicated by the disappearance of the yellow color. Cool the solution, add 75 ml. of glacial acetic acid with stirring, dilute to the mark with distilled water and mix well. Phenylhydrazine. One % aqueous solution of phenylhydrazine hydro- chloride. Potassium Ferricyanide. Ten % aqueous solution of potassium fer- ricyanide prepared fresh weekly. Standard ztllantoin Solution. Accurately weigh out 1.000 g. of al- lantoin and dissolve it in approximately 50 ml. of distilled water with the aid of heat. Transfer this solution to a 100 ml. volumetric flask and dilute to the mark with distilled water. The solution contains 10.0 rag. of allantoin/ml. This solution should be prepared fresh weekly. B. Copper Tartrate Folin ztcid Molybdate Method (¾) Preparation of Calibration Curve. Transfer 2.00, 4.00, 6.00, 8.00 and 10.00 ml. aliquots of the standard allantoin solution to individual 100 ml.