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Octyl isobutyrate
Fragrance raw materials monographs
893
OCTYL ISOBUTYRATE
Structure: CHa- [CH217" OCO" CH(CH3)2. Description and physical properties: A colourless liquid. Occurrence: Reported to be found among the volatile components of hops (Fenaroli's Handbook of Flavor Ingredients, 1971). Preparation: By azeotropic esteriflcation of n-octanol with isobutyric acid (Arctan'der, 1969). Uses: In public use since the 1950s. Use in fragrances in the USA amounts to less than "1000 lb/yr. Concentration in final product (%): Usual Maximum
Soap 0-005 0"05
Detergent 0.0005 0-0005
Creams, lotions 0-0025 0-02
Pesfume 0"03 0.2
Status Octyl isobutyrate was given GRAS status by FEMA (1965) and is approved by the FDA for food use (21 CFR 121.1164). The Council of Europe (1974) included octyl isobutyrate at a level of 5 ppm in the list of artificial flavouring substances that may be added to foodstuffs without hazard to public health.
Biological data Acute toxicity. Both the acute oral LDso in rats and the acute dermal LDso in rabbits exceeded 5 g/kg (Levenstein, 1974). Irritation. Octyl isobutyrate applied full strength to intact or abraded rabbit skin for 24 hr under occlusion was not irritating (Levenstein, 1974). Tested at 2% in petrolatum, it produced no irritation after a 48-hr closed-patch test on human subjects (Epstein, 1974). Sensitization. A maximization test (Kligman, 1966; Kligman & Epstein, 1975) was carried out on 26 volunteers. The material was tested at a concentration of 2% in petrolatum and produced no sensitization reactions (Epstein, 1974). Metabolism. Isobutyrates are hydrolysed to materials that are either normally in the diet or readily converted to such materials (Fassett, 1963a). Isobutyric acid occurs normally in the metabolism of valine, being converted to a propionyl group and entering into the glycogenic process (Fassett, 1963b). n-Octanol is largely oxidized in vivo; about 10% is excreted conjugated with glucuronic acid in rabbits. Isomeric octanols may be more highly conjugated; they may also be oxidized to the ketone or may be excreted unchanged (Williams, 1959). Micro-organisms. Octyl isobutyrate in a dilution of 1:500 had no inhibitory effect in vitro on growing cultures of four bacteria (Maruzzella & Bramnick, 1961). The vapour of octyl isobutyrate had no inhibitory effect on growing cultures of four fungi (Maruzzella, Chiaramonte & Garofalo, 1961).
References Arctander, S. (1969). Perfume and Flavor Chemicals (Aroma Chemicals). Vol. 2. no. 2412. S. Arctander, Montclair, New Jersey. Council of Europe (1974). Natural Flavouring Substances, Their Sources, and Added Artificial Flavouring Substances. Partial Agreement in the Social and Public Health Field. List 1, no. 593, p. 250. Strasbourg. Epstein, W. L. (1974). Report to RIFM, 19 August. Fassett, D. W. (1963a). Esters. In Industrial Hygiene and Toxicology. 2nd ed. Edited by F. A. Patty. Vol. II, p. 1865. Interscience Publishers, New York. Fassett, D. W. (1963b). Organic acids and related compounds. In Industrial Hygiene and Toxicology. 2nd ed. Edited by F. A. Patty. Vol. II, p. 1782. Interscience Publishers, New York. Fenaroli's Handbook of Flavor Ingredients (1971). Edited by T. E. Furia and N. Bellanca. p. 559. Chemical Rubber Co., Cleveland, Ohio. Flavoring Extract Manufacturers' Association (1965). Survey of flavoring ingredient usage levels. No. 2808. Fd Technol., Champaign 19 (2), part 2. 155.
894
D . L . J . OPDYKE
Kligman, A. M. (1966). The identification of contact allergens by human assay. III. The maximization test. A procedure for screening and rating contact sensitizers. J. invest. Derm. 47, 393. Kligman, A. M. & Epstei.n, W. (1975). Updating the maximization test for identifying contact allergens. Contact Dermatitis 1.231. Levenstein, I. (1974). Report to RIFM, 17 July. Maruzzella, J. C. & Bramnick, E. (1961). The antibacterial properties of perfumery chemicals. Soap Perfum. Costa. 34. 743. Maruzzella, J. C., Chiaramonte, J. S. & Garofalo, M. M. (1961). Effects of vapors of aromatic chemicals on fungi. J. pharm. Sci. 50. 665. Williams, R. T. (1959). Detoxication Mechanisms. The Metabolism and Detoxication of Drugs, Toxic Substances and Other Organic Compounds. 2nd ed., pp. 48 & 63. Chapman & Hall Ltd., London.
893
OCTYL ISOBUTYRATE
Structure: CHa- [CH217" OCO" CH(CH3)2. Description and physical properties: A colourless liquid. Occurrence: Reported to be found among the volatile components of hops (Fenaroli's Handbook of Flavor Ingredients, 1971). Preparation: By azeotropic esteriflcation of n-octanol with isobutyric acid (Arctan'der, 1969). Uses: In public use since the 1950s. Use in fragrances in the USA amounts to less than "1000 lb/yr. Concentration in final product (%): Usual Maximum
Soap 0-005 0"05
Detergent 0.0005 0-0005
Creams, lotions 0-0025 0-02
Pesfume 0"03 0.2
Status Octyl isobutyrate was given GRAS status by FEMA (1965) and is approved by the FDA for food use (21 CFR 121.1164). The Council of Europe (1974) included octyl isobutyrate at a level of 5 ppm in the list of artificial flavouring substances that may be added to foodstuffs without hazard to public health.
Biological data Acute toxicity. Both the acute oral LDso in rats and the acute dermal LDso in rabbits exceeded 5 g/kg (Levenstein, 1974). Irritation. Octyl isobutyrate applied full strength to intact or abraded rabbit skin for 24 hr under occlusion was not irritating (Levenstein, 1974). Tested at 2% in petrolatum, it produced no irritation after a 48-hr closed-patch test on human subjects (Epstein, 1974). Sensitization. A maximization test (Kligman, 1966; Kligman & Epstein, 1975) was carried out on 26 volunteers. The material was tested at a concentration of 2% in petrolatum and produced no sensitization reactions (Epstein, 1974). Metabolism. Isobutyrates are hydrolysed to materials that are either normally in the diet or readily converted to such materials (Fassett, 1963a). Isobutyric acid occurs normally in the metabolism of valine, being converted to a propionyl group and entering into the glycogenic process (Fassett, 1963b). n-Octanol is largely oxidized in vivo; about 10% is excreted conjugated with glucuronic acid in rabbits. Isomeric octanols may be more highly conjugated; they may also be oxidized to the ketone or may be excreted unchanged (Williams, 1959). Micro-organisms. Octyl isobutyrate in a dilution of 1:500 had no inhibitory effect in vitro on growing cultures of four bacteria (Maruzzella & Bramnick, 1961). The vapour of octyl isobutyrate had no inhibitory effect on growing cultures of four fungi (Maruzzella, Chiaramonte & Garofalo, 1961).
References Arctander, S. (1969). Perfume and Flavor Chemicals (Aroma Chemicals). Vol. 2. no. 2412. S. Arctander, Montclair, New Jersey. Council of Europe (1974). Natural Flavouring Substances, Their Sources, and Added Artificial Flavouring Substances. Partial Agreement in the Social and Public Health Field. List 1, no. 593, p. 250. Strasbourg. Epstein, W. L. (1974). Report to RIFM, 19 August. Fassett, D. W. (1963a). Esters. In Industrial Hygiene and Toxicology. 2nd ed. Edited by F. A. Patty. Vol. II, p. 1865. Interscience Publishers, New York. Fassett, D. W. (1963b). Organic acids and related compounds. In Industrial Hygiene and Toxicology. 2nd ed. Edited by F. A. Patty. Vol. II, p. 1782. Interscience Publishers, New York. Fenaroli's Handbook of Flavor Ingredients (1971). Edited by T. E. Furia and N. Bellanca. p. 559. Chemical Rubber Co., Cleveland, Ohio. Flavoring Extract Manufacturers' Association (1965). Survey of flavoring ingredient usage levels. No. 2808. Fd Technol., Champaign 19 (2), part 2. 155.
894
D . L . J . OPDYKE
Kligman, A. M. (1966). The identification of contact allergens by human assay. III. The maximization test. A procedure for screening and rating contact sensitizers. J. invest. Derm. 47, 393. Kligman, A. M. & Epstei.n, W. (1975). Updating the maximization test for identifying contact allergens. Contact Dermatitis 1.231. Levenstein, I. (1974). Report to RIFM, 17 July. Maruzzella, J. C. & Bramnick, E. (1961). The antibacterial properties of perfumery chemicals. Soap Perfum. Costa. 34. 743. Maruzzella, J. C., Chiaramonte, J. S. & Garofalo, M. M. (1961). Effects of vapors of aromatic chemicals on fungi. J. pharm. Sci. 50. 665. Williams, R. T. (1959). Detoxication Mechanisms. The Metabolism and Detoxication of Drugs, Toxic Substances and Other Organic Compounds. 2nd ed., pp. 48 & 63. Chapman & Hall Ltd., London.