Butyl phthalate, interacting with

Biomarkers Used to Characterize Effects Caused by Di- -butyl Phthalate INTERACTIONS WITH OTHER CHEMICALS... 

Limited information was located regarding possible interactions of DEHP with other chemicals in humans. Urinary measurements of the monoester metabolites of seven common phthalates in 289 adults from the U.S. population, determined using the selective and sensitive analytical approach discussed in Section 3.8.1 (Biomarkers Used to Identify or Quantify Exposure to DEHP), showed detectable levels of monoethyl phthalate (95th percentile concentration, 3,750 ppb), monobutyl phthalate (294 ppb), monobenzyl phthalate (137 ppb), 2-ethylhexyl phthalate (21.5 ppb), cyclohexyl phthalate (8.6 ppb), isononyl phthalate (7.3 ppb), and octyl phthalate (2.3 ppb), reflecting exposure to DEHP, dibutyl phthalate, benzyl butyl phthalate, di-(2-ethylhexyl) phthalate, dicyclohexyl phthalate, di-isononyl phthalate, and dioctyl phthalate, respectively (Blount et al. 2000a). Considering evidence such as this which indicates that co-exposure to multiple phthalates can occur, as well as the likelihood that many of these compounds exert effects via a common mechanism of action, there is a potential for interactions between DEHP and other phthalate esters. 

An IR spectroscopy technique was developed to study the plasticiser migration from polymer compositions to the air environment. The applicability of the method was demonstrated for filled PVC compositions plasticised with di-n-butyl phthalate. Values for the effective diffusion coefficient(D) of the plasticiser were calculated from the spectroscopic data. An increase in the chalk content in a PVC composition led to a monotonic increase in D, whereas kaolin-filled compositions exhibited a more complex behaviour. The observed pattern of changes in D with varying filler content was correlated with the competing interaction of components in the system. 20 refs. (Full translation of Vys.Soed.B, 44, No.2, 2002, p.363-8)... 

One mechanism of toxicity proposed for all phthalate esters that cause testicular toxicity involves interference with the interaction of follicle stimulating hormone (FSH) with the FSH receptor on Sertoli cells (NTP 2000). This mechanism may be applicable to di- -butyl phthalate, but no studies regarding this mechanism and di- -butyl phthalate were located. 

Administration of zinc provides some protection against the testicular toxicity of di- -butyl phthalate exposure in rats (Cater et al. 1977). No other studies were located regarding the interaction of di- -butyl phthalate with other chemicals. Schulsinger and Mullgaard (1980) reported that humans exposed to a mixture of three phthalate esters, including di- -butyl phthalate, did not develop dermal sensitization, but since di- -butyl phthalate is negative for skin sensitization, these results shed little light on possible interactions. 

The available toxicokinetic data did not evaluate the potential differences between adults and children, although there is some evidence that there are age-related differences in the activity of at least one enzyme, UDP-glucoronsyltransferase, that is involved in the metabolism of di- -butyl phthalate. Toxicokinetic studies examining how aging can influence the absorption, distribution, and excretion of di- -butyl phthalate would be useful in assessing children s susceptibility to di- -butyl phthalate toxicity. The mechanism of action for a number of toxic effects have not been elucidated. There are no data to determine whether there are age-specific biomarkers of exposure or effects or any interactions with other chemicals that would be specific for children. There is very little available information on methods for reducing di- -butyl phthalate toxic effects or body burdens it is likely that research in adults would also be applicable to children. 

Okada S, Tamemasa 0. 1978. [Distribution and metabolism of di-( -butyl)-phthalate in mice and its interaction with nucleic acids and proteins.] Yakugaku Zasshi 98 1229-1235. (Japanese)... 

Figure 5.7 Capillary force versus distance for a sphere of 1.5 cm radius interacting with another sphere ofsimilar radius (open circles) andwith a plane (filled circles). The spheres are in aqueous medium and the menisci are formed by a mixture of di-n-butyl phthalate and a liquid...

---