O-Cresylic

A particular mode of neurotoxicity was discovered for tricresyl phosphate that correlated with the presence of the o-cresyl isomer (or certain other specific aLkylphenyl isomers) in the triaryl phosphates. Many details of the chemistry and biochemistry of the toxic process have been elucidated (139,140,143—146). The use of low ortho-content cresols has become the accepted practice in industrial production of tricresyl phosphate. Standard in vivo tests, usually conducted with chickens sensitive to this mode of toxicity, have been developed for premarket testing of new or modified triaryl phosphates. As of 1992, the EPA called for extensive new toxicity and environmental data on this group of products (147). The Vederal e ster AoQ xm. ci. calling for this... 

Common Name o-Cresyl glycerol ether, glyceryl O-tOlyl ether, cresoxypropanediol, cres-oxydlol... 

FIGURE 24.4 Master curves of the local segmental relaxation times for 1,4-polyisoprene (-y = 3.0) 1,2-polybutadiene (7=1.9) polyvinylmethylether (7 = 2.55) polyvinylacetate (7 = 2.6) polypropylene glycol (7 = 2.5) polyoxybutylene (7 = 2.8) poly(phenyl glycidyl ether)-co-formaldehyde (7 = 3.5) polymethylphe-nylsiloxane (7 = 5.6) poly[(o-cresyl glycidyl ether)-co-formaldehyde] (7 = 3.3) and polymethyltolylsiloxane (PMTS) (7 = 5.0) [15 and references therein]. Each symbol for a given material represents a different condition of T and P. 

After a single dermal exposure to waste from the reclamation of a Fyrquel hydraulic fluid that may have been contaminated with tri-or/7 o-cresyl phosphate (TOCP), no apparent signs of neurotoxicity were observed in calves of 10 cows that manifested neurotoxicity just after the birth of the calves. The cows were apparently also exposed orally concurrent to the dermal exposure (Julian et al. 1976). No intermediate- or chronic-duration dermal studies examining developmental effects in animals were located. 

Single dermal doses of 50 mg/kg tri-ort/ o-cresyl-[uniformly labeled 14C-phenyl]phosphate (TOCP) were applied to preclipped, unprotected, 10-cm2 areas of skin in male cats (Nomeir and Abou-Donia 1986). 

Major components Chemical formula Chemical structure Identification numbers Tri-o-cresyl phosphate C2iH2i04P (RO) (RO) (RO) P=0 Predominantly saturated hydrocarbons predominantly in the range C15 through C30 Hydrocarbons predominantly in the range C11 through C20... 

Property Tri-n-butyl phosphate Tris(isopropyl phenyl)phosphate T ri-o-cresyl phosphate... 

Abou-Donia MB, Suwita E, Nomeir AA. 1990a. Absorption, distribution, and elimination of a single oral dose of [14C]tri-orf/ o-cresyl phosphate in hens. Toxicology 61 13-25. 

Somkuti SG, Lapadula DM, Chapin RE, et al. 1987a. Reproductive tract lesions resulting from subchronic administration (63 days) of tri-o-cresyl phosphate in male rats. Toxicol Appl Pharmacol 89 49-63. 

Suwita E, Abou-Donia MB. 1990. Pharmacokinetics and metabolism of a single subneurotoxic oral dose of tri-o-cresyl phosphate in hens. Arch Toxicol 64 237-241. 

Tri-o-cresyl phosphate, t452 Tricyclene, t400a Tricyclo[3.3.1.13=7]decane, a65... 

For definition of k3 see equation 2 substrates used o-cresyl /3-D-gluco-pyranoside and o-cresyl /3-n-galactopyranoside. 

S. G. Somkuti, M. B. Abou-Donia, Distribution, Elimination and Metabolism of Tri-o-cresyl Phosphate Following Daily Oral Administration in Fischer 344 Male Rats , Arch. Toxicol. 1990, 64, 572-579. 

BUTYL-HEXADECYL-SULFIDE DECYL-SULFIDE ETHYL-OCTADECYL-SULFIDE HEPTADECYL-PROPYL-SULFIDE HETHYL-NONADECYL-SULFIDE 1-EICOSANETHIOL DECYL-DISULFIDE TRI-o-CRESYL PHOSPHATE 1-PHENYLPENTADECANE 1-CYCLOPENTYLHEXADECANE 1-CYCLOHEXYLPENTADECANE 1-PHENYLHEXADECANE 1-CYCLOHEXYLHEXADECANE n-BUTYL STEARATE DIISOOCTYL PHTHALATE DIOCTYL PHTHALATE DINONYLPHENOL TETRAPHENYLETHYLENE DIISODECYL PHTHALATE... 

Synonyms AI3-00137 BRN 0506917 CCRIS 646 2-Cresol o-Cresol o-Cresylic acid EINECS 202-423-8 FEMA No. 3480 l-Hydroxy-2-methylbenzene 2-Hydroxytoluene o-Hydroxytoluene 2-Methylhydroxybenzene o-Methylhydroxybenzene o-Methylphenol o-Methylphenylol NSC 23076 Orthocresol o-Oxytoluene RCRA waste number U052 2-Toluol o-Toluol UN 2076. 

Synonyms AI3-00520 BRN 1892885 CCRIS 6421 o-Cresyl phosphate EINECS 201-103-5 Fyrquel 150 NSC 438 Phosflex 179-C Phosphoric acid, tris(2-methylphenyl) ester Phosphoric acid, tri-2-tolyl ester Phosphoric acid, tri-o-cresyl ester o-TCP TCP TOCP TOFK o Tolyl phosphate TOTP Tricresyl phosphate Triorthocresyl phosphate Tri-2-methylphenyl phosphate Tris(o-cresyl)phosphate Tris(o-methylphenyl)phosphate Tris(o-tolyl)phosphate Tri-2-tolyl phosphate Tri-o-tolyl phosphate. 

Chemical/Physical. Tri-o-cresyl phosphate hydrolyzed rapidly in Lake Ontario water, presumably to di-o-cresyl phosphate (Howard and Doe, 1979). When an aqueous solution containing a mixture of isomers (0.1 mg/L) and chlorine (3 to 1,000 mg/L) was stirred in the dark at 20 °C for 24 h, the benzene ring was substituted with one to three chlorine atoms (Ishikawa and Baba, 1988). 

Benzyl butyl phthalate Benzo [ 6] fluoranthene Benzo [A] fluoranthene Benzol a] pyrene Benzo lei pyrene Tri-o-cresyl phosphate Strychnine Benzo ghi pery lene Indenoll,2,3-crfl pyrene Dibenzo la, A1 anthracene Bis(2-ethylhexyl) phthalate Di-n-octyl phthalate Ammonia... 

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