IDENTIFICATION AND USE: At room temperature, the low molecular-weight ester isoamyl acetate (IAA) is a clear liquid with an intense sweet, but pleasant, banana or pear-like odor. In alcohol solutions, mineral waters and syrups it is used as a pear flavor. It is also used as solvent for old oil colors, for tannins, nitrocellulose, lacquers, celluloid and camphor; swelling bath sponges; covering unpleasant odors, perfuming shoe polish; manufacturing artificial silk, leather, or pearls, photographic films, celluloid cements, waterproof varnishes, bronzing liquids, and metallic paints; dying and finishing textiles. Honey bees use IAA as an alarm pheromone, and store IAA in their poison sting. Due to its strong smell, which can be perceived at low concentrations, and because of supposedly low toxicity, IAA is used to test the effectiveness of respirators or gas masks.
HUMAN EXPOSURE AND TOXICITY: There is a case of a patient who developed a severe reversible extrapyramidal syndrome after inhalation of IAA. IAA vapor is known to irritate eyes, skin and respiratory tract, and to cause mild unspecific central nervous system symptoms. No evidence of delayed contact hypersensitivity, phototoxicity, or photoallergy due to amyl acetate or IAA was observed in human repeat insult patch test studies. It is concluded that amyl acetate and isoamyl acetate are safe as presently used in cosmetic products.
ANIMAL STUDIES: Several drops of liquid amyl acetate squirted on eyes of rabbits & washed off with water 2 min later caused temporary corneal epithelial injury, but recovery was complete in a day or two. Isoamyl acetate given to dogs at 5000 ppm (27 mg/L) for 1 hr caused nasal irritation & drowsiness. Irritation, weakness, and loss of weight was observed in cats exposed to a concentration of 1900 ppm (10 mg/L) for 8 hours for 6 days; 4000 ppm (21 mg/L) for 20 min irritated the eyes and nose; and light CNS depression & delayed death were observed in cats exposed to 7200 ppm (38 mg/L) for 24 hr. IAA is not genotoxic, it tested non-mutagenic in a series of mutagenic assays. |