PRINCIPLES OF TOXICOLOGY - Biology East Borneo

16.12 TOXIC PROPERTIES OF REPRESENTATIVE ETHERS 391Figure 16.17 Ether compounds.used as an anesthetic at one time, but it is slightly irritating to the skin and contact with the eyes shouldbe avoided. It produces anesthesia in humans in a concentration range of 3.6–6.5 percent in air, butrespiratory arrest occurs at 7–10 percent, providing only a small margin of safety. Ether can produceprofound muscular relaxation by means of corticospinal and neuromuscular blockade. However,nausea and vomiting are common subsequent side effects and were limiting factors in its use.Isopropyl ether (see Figure 16.19) (or diisopropyl ether) is comparatively more toxic than ethylether, and causes irritation at much lower concentrations than those which are required to produceanesthetic effects. This effectively limits its use as an anesthetic. In humans, 500 ppm for 15 min causesno irritation, but odor is noticeably unpleasant at 300 ppm. At 800 ppm, disagreeable irritation of theeyes and nose is noticeable.Figure 16.18 Ethyl ether.Figure 16.19 Isopropyl ether.Other EthersThe unsaturated ethers are, in general, more toxic than the saturated ethers, produce anesthesia faster,and possibly cause liver damage. Divinyl ether is more potent than ethyl ether. Halogenated ethers cancause very severe irritation to the skin, eyes, and lungs. For example, the vapors of chloromethyl ethersare painful at 100 ppm. The chlorinated ethers may also be potent alkylating agents, and compoundssuch as bis(dichloromethyl) ether are classified as carcinogens by some regulatory agencies (see alsoChapter 13). Aromatic ethers, on the other hand, generally are less volatile, less irritating, and lesstoxic than the alkyl ethers.The solvent 1,4-dioxane (or diethylene dioxide) is a member of the glycol ethers and is used in awide range of lacquers, paints, dyes, cosmetics, deodorants, stains, and detergent products. It shouldbe carefully distinguished from the dioxins (e.g., 2,3,7,8-tetrachlorodibenzodioxin; or 2,3,7,8-TCDD)in any discussions of toxicity and environmental. Liquid dioxane is a painful irritant to the eyes andskin, and can be absorbed dermally in significant quantities. Renal and hepatic damage may be