014. Dilauryl thiodipropionate (FAO Nutrition Meetings Report Series 38a)

WHO/Food Add./24.65 FAO Nutrition Meetings Report Series No. 38A SPECIFICATIONS FOR IDENTITY AND PURITY AND TOXICOLOGICAL EVALUATION OF SOME ANTIMICROBIALS AND ANTIOXIDANTS The content of this document is the result of the deliberations of the Joint FAO/WHO Expert Committee on Food Additives which met 8-17 December 1964^a ^a Eighth Report of the Joint FAO/WHO Expert Committee on Food Additives, Wld Hlth Org. techn. Rep. Ser., 1965, 309; FAO Nutrition Meetings Report Series 1965, 38. DILAURYL THIODIPROPIONATE CHEMICAL NAMES Dilauryl ester of ß,ß'-thiodipropionic acid; dilauryl ester of 3,3'-thiodipropionic acid EMPIRICAL FORMULA C₃₀H₅₈O₄S STRUCTURAL FORMULA CH₂ - CH₂ - COO - (CH₂)₁₁ - CH₃ ' S ' CH₂ - CH₂ - COO - (CH₂)₁₁ - CH₃ MOLECULAR WEIGHT 514.86 DEFINITION Dilauryl thiodipropionate is an ester of thiodipropionic acid and a food grade lauryl alcohol. It contains not less than 99% of C₃₀H₅₈O₄S and conforms to the following specifications. DESCRIPTION White crystalline flakes having a characteristic sweetish ester-like odour. USE As an antioxidant for fats and other foodstuffs. IDENTIFICATION A. Solubility: Water: Insoluble Organic solvent: Soluble in most organic solvents B. Solidification point: Not below 40° C. Saponification number: Not less than 210 PURITY TESTS Acidity (as thiodipropionic acid): Not more than 0.2% of C₆H₁₀O₄S. To 50 ml of a mixture of 1 part of methanol and 3 parts benzene add phenolphthalein TS and neutralize with ethanolic potassium hydroxide. Add 2 g, accurately weighed, of dilauryl dithiopropionate, swirl to dissolve, add 3 drops of phenolphthalein TS and titrate with 0.1 N ethanolic potassium hydroxide. Each ml of 0.1 N ethanolic potassium hydroxide is equivalent to 8.91 mg of C₆H₁₀O₄S. Heavy metals: Not more than 20 mg/kg. Place 2 g, accurately weighed, in a porcelain crucible, add sufficient nitric acid to wet the sample and ignite carefully at a low temperature until thoroughly charred, covering the crucible loosely with a porcelain lid during the ignition. When carbonization is complete, add 2 ml of nitric acid and 5 drops of sulfuric acid, heat cautiously until white fumes are evolved, and then ignite, preferably in a muffle furnace at 550° ± 50° until the carbon is removed. Cool, add 1 ml of diluted hydrochloric acid (1 in 2), cover, and digest on a steam bath for 15 minutes. Remove the cover and evaporate on a steam bath to dryness. Moisten the residue with 0.05 ml of hydrochloric acid, add 10 ml of hot water, and digest on a steam bath for 5 minutes. Filter if necessary and dilute to 25 ml. Arsenic: Not more than 3 mg/kg. Lead: Not more than 10 mg/kg. ASSAY Weigh 0.700 g of dilauryl thiodipropionate and add 10 ml of acetic acid and 50 ml of ethanol, and heat the mixture gently until the sample dissolves completely. Add 3 ml of hydrochloric acid and 4 drops of p-ethoxychrysoidin TS and immediately titrate with 0.1 N bromide-bromate TS. As the endpoint is approached (pink colour), add 4 more drops of the indicator solution and continue the titration, dropwise, to a colour change from red to pale yellow. Perform a blank determination and make any necessary correction. Each ml of 0.1 N bromide-bromate TS is equivalent to 0.02574 g of C₃₀H₅₈O₄S. Subtract the per cent. of thiodipropionic acid determined in the acidity tests from the per cent. of dilauryl thiodipropionate calculated from this titration to obtain the per cent. of C₃₀H₅₈O₄S. Biological Data Biochemical aspects No information available. Acute Toxicity Animal Route LD₅₀ Reference (mg/kg body-weight) Thiodipropionic Mouse oral 2000 1 acid Mouse intraperitoneal 250 1 Mouse intravenous 175 1 Rat oral 3000 1 Rat intraperitoneal 500 1 Rat intravenous >300 1 Dilauryl Mouse oral >2000 1 thiodipropionate Mouse intraparitoneal >2000 1 Rat oral >2500 1 Distearyl Mouse oral >2000 1 thiodipropionate Mouse intraperitoneal >2000 1 Rat oral >2500 1 Short-term studies Rat. Mixtures of thiodipropionic acid and dilauryl thiodipropionate were heated with lard in concentrations at least 10 times that recommended for use and fed to rats. There was no detectable toxic effect.¹ Guinea-pig. Thiodipropionic acid was fed to guinea-pigs at a level of 0.5% in the drinking-water for a period of 120 days. No significant effect was noted on weight or mortality.¹ Dog. Dogs were fed a mixture of 10 parts by weight of dilauryl thiodipropionate and 1 part of thiodipropionic acid in the diet at concentrations of 0.1% and 3.0% of the acid-ester mixture. No untoward effects were noted over a period of 100 days. Long-term studies Rat. Thiodipropionic acid or its dilauryl or distearyl ester was fed to groups of 20 rats each at levels of 0%, 0.5%, 1.0% and 3.0% in the diet for a period of 2 years. No discernable adverse effects were observed in any of the experimental animals, as determined by growth rate, mortality, and pathological examination.¹ Comment on experimental studies reported It would be desirable to have further details on the experimental work that has been carried out on thiodipropionic acid; the published report gives only a summary. Biochemical studies and observations on human subjects are not available. Evaluation Level causing no significant toxicological effect in the rat 3.0% (= 30 000 ppm) in the diet, equivalent to 1500 mg/kg body-weight per day. Estimate of acceptable daily intakes for man mg/kg body-weight Unconditional acceptance 0-3.0 Conditional acceptance 3.0-15.0 Further Work Considered Desirable 1. Long-term studies in a species other than the rat. 2. Biochemical studies in animals and in man. Reference 1. Lehman, A. J., Fitzhugh, O. G., Nelson, A. A. & Woodard, G. (1951) Advanc. Food Res., 3, 197

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       Toxicological Abbreviations
       DILAURYL THIODIPROPIONATE (JECFA Evaluation)