International Journal of Pharmaceutics 229 (2001) 139–146

Comparative study of the leachability of di(2-ethylhexyl)phthalate and tri(2-ethylhexyl) trimellitate from

haemodialysis tubing

K. Kambia a, T. Dine a,*, R. Azar b, B. Gressier a, M. Luyckx a, C. Brunet a

a Laboratoire de Pharmacologie, Pharmacocinetique et Pharmacie Clinique, Faculte des Sciences Pharmaceutiques et Biologiques,3 rue du Professeur Laguesse, BP 83, 59006 Lille Cedex, France

b Ser�ice de Nephrologie et d’Hemodialyse, Departement de Medecine Interne B, Centre Hospitalier General de Dunkerque,A�. L. Herbaux, BP 6-367, 59385 Dunkerque, France

Received 26 January 2001; received in revised form 23 July 2001; accepted 31 July 2001

Abstract

The leachability of both Di(2-ethylhexyl) phthalate (DEHP) and Tri(2-ethylhexyl) trimellitate (TEHTM) or Trioctyltrimellitate (TOTM) from haemodialysis tubing was investigated in 20 patients with chronic renal failure undergoingmaintenance haemodialysis. The blood tubing made of common polyvinyl chloride (PVC) plasticized with DEHP(group 1 patients) were replaced with tubing plasticized with TOTM-DEHP (group 2 patients). The patient bloodobtained from the inlet and the outlet of the dialyzer was analyzed during a 4 h-dialysis session. Thus, the circulatingconcentrations of both DEHP and TOTM resulting from the release from dialyzer tubes were estimated usingHigh-performance Liquid chromatograph (HPLC). With the common PVC-DEHP blood tubing, a DEHP quantityof 122.95�33.94 mg was extracted from tubing during a single dialysis session (ranging from 55 to 166.21 mg).During the same period, the total amounts of DEHP retained by the patients were 27.30�9.22 mg (ranging from12.50 to 42.72 mg). As for blood tubing plasticized with TOTM-DEHP, 41.80�4.47 mg of DEHP and 75.11�25.72mg of TOTM were extracted. During the same period, the amounts of DEHP and TOTM retained by the patientswere 3.42�1.37 mg and 4.87�2.60 mg, respectively. The extraction rate both plasticizers was correlated with serumlipid content (cholesterol+ triglyceride) (r2=0.75 for DEHP and r2=0.64 for TOTM). In the present investigation,less TOTM and DEHP were apparently released from haemodialysis tubing plasticized with TOTM-DEHP thanDEHP released from haemodialysis tubing plasticized with DEHP only. TOTM seems to be a superior alternative toDEHP for use in medical devices because of its potential lower leachability. To recommend it as an alternativeplasticizer, its possible toxicity towards human body should be investigated before it can be used routinely. However,patients undergoing haemodialysis using tubing plasticized with DEHP only are regularly exposed to non negligibleamounts of DEHP. In view of several biological effects previously reported, it is time to reconsider the use of DEHPonly as a plasticizer. © 2001 Published by Elsevier Science B.V.

Keywords: TOTM; DEHP; PVC; Release; Haemodialysis patients

www.elsevier.com/locate/ijpharm

* Corresponding author. Tel.: +33-320-964040; fax: +33-320-969752.E-mail address: tdine@phare.univ-lille2.fr (T. Dine).

0378-5173/01/$ - see front matter © 2001 Published by Elsevier Science B.V.

PII: S 0378 -5173 (01 )00840 -7

K. Kambia et al. / International Journal of Pharmaceutics 229 (2001) 139–146140

1. Introduction

Polyvinyl chloride (PVC) plasticized withDEHP found wide use in medical and paramedi-cal appliances as well as in food storage packag-ing (Martis et al. 1987; Rathinam, 1988). For thisreason, a number of phthalic acid esters, includingdi(2-ethylhexyl) phthalate (DEHP), have beensubjected to fairly extensive safety testing. Sincethe toxicity of DEHP towards animals was sus-pected (Parmar et al., 1995; Peters et al., 1997;Doull et al., 1999), an intensive research on new,biologically inert plasticizers to be used in bloodbags, haemodialysis material has been initiated.Among the alternative plasticizer studied, tri(2-ethylhexyl) trimellitate (TEHTM or TOTM) hasbeen increasingly attractive (Flaminio et al.,1988).

TOTM (an ester of trimellitic acid) like DEHP(an ester of phthalic acid) was used in such medi-cal devices, had applications in pool liners, furni-ture, outwear and weather-stripping (Martis et al.,1987). However, very little information was avail-able on its biological effects. Before using TOTMas an alternative plasticizer to DEHP, some stud-ies including toxicity, disposition and metabolism,are required.

It is clear that a non negligible amounts ofDEHP leaches from PVC into blood products(Dine et al., 1991; Turner et al., 1995), into intra-venous solution (Faouzi et al., 1995) and intopatients undergoing maintenance haemodialysis(Pollack et al. 1985; Faouzi et al., 1999). On theother hand, the exposure of laboratory animals tohigh DEHP doses resulted in various biologicaleffects, including testicular atrophy in rats(Flaminio et al., 1988; Parmar et al., 1995), prolif-eration of peroxisomes in rodents (Bojes andThurman, 1994; Doull et al., 1999) and livertumors in rats and mice (Kluwe et al. 1982; Reddyand Lalwani 1984). In addition, studies in rodentshave shown that DEHP can induce severalchanges in hepatic morphology and biochemicalfunctions (Van Den Munckhof et al., 1998). Inview of these findings in animals, intensive re-searches on alternative non toxic plasticizers hasbeen carried out including the current investiga-tion on TOTM as a plasticizer having negligible

leachability (Flaminio et al., 1988; Rathinam,1988; Christensson et al., 1991). With regard tohaemodialysis patients using dialysis tubing plasti-cized with DEHP only, the estimated values previ-ously reported for DEHP exposure range widely(Pollack et al., 1985; Nassberger et al., 1987;Faouzi et al., 1999). For the new dialysis tubingplasticized with TOTM-DEHP, little is knownabout the real exposure of both plasticizers.

The aim of this study was to quantify theamounts of both DEHP and TOTM released intothe blood of haemodialyzed patients using thenew dialysis tubing plasticized with TOTM-DEHP and to compare them with the amounts ofDEHP released when the plasticizer was DEHPonly.

2. Materials and methods

2.1. Subjects

Before entering the study, each patient hadbeen on haemodialysis treatment for periods rang-ing from 1 to 7 years. Consent was obtained fromall subjects. Patients, with congestive heart failure,pulmonary oedema, hepatic or acute renal failurewere not included in the study. Plasma levels ofTOTM or DEHP were determined for two groupsof patients:

Group 1: 10 patients (seven men and threewomen) aged 61–86 years old with chronic renalfailure on maintenance haemodialysis in the dialy-sis Unit of Dunkerque Hospital, (France) partici-pated in the study using classic tubing plasticizedwith DEHP only.

Group 2: 10 patients (eight men and twowomen) aged 37–75 years old with chronic renalfailure on maintenance haemodialysis in the dialy-sis Unit of Dunkerque Hospital, (France) partici-pated in the study using the new tubing plasticizedwith TOTM-DEHP.

Each patient underwent dialysis for a 4 h-pe-riod three times a week, with a double needleaccess in arterio-venous fistulas. The dialysateflow rate was maintained at 500 ml/min and theblood flow rate in the haemodialysis circuit mea-sured by pump revolutions and bubble transittime was maintained approximately 300 ml/min.

K. Kambia et al. / International Journal of Pharmaceutics 229 (2001) 139–146 141

2.2. Chemicals

DEHP and its internal standard, Di-n-heptylphthalate (DNHP), TOTM and its internal stan-dard Di-n-decyl phthalate (DNDP), were ob-tained from commercial sources purchased fromSigma-Aldrich (Saint-Quentin-Fallavier, France)and were used as analytical standards withoutfurther purification. HPLC-grade acetonitrile andhexane were purchased from SDS (ZI de ValdomePeypin, France) and from Sigma-Aldrich respec-tively and both were assayed for the presence ofDEHP and TOTM. Analytical grade sodium hy-droxide, phosphoric acid and triethylamine wereobtained from Prolabo (Paris, France). The waterused to prepare aqueous buffers was de-ionizedand purified by distillation (Milli-Q, Millipore,Saint-Quentin Yvelines, France). To minimize therisk of contamination with DEHP and TOTMduring samples handling and analysis, all theglasswares used in the study were previouslywashed using tetrahydrofuran-methanol mixturethen rinsed with hexane. All the other reagentsused were analytical grade or better.

2.3. Analytical method

Chromatographic analysis was performed usingan HP 1090 high-performance liquid chro-matograph (Hewlett-Packard, Orsay, France)equipped with a variable-volume injector, an au-tomatic sampling system and a Hewlett-PackardModel 79994A diode-array UV detector operatingat 202 and at 215 nm for DEHP and for TOTMrespectively. The output from the detector wasconnected to a Hewlett-Packard 9000 Model 300integrator and the data were recorded on a HPThinkjet printer. Separation was achieved using a5 �m Waters Spherisorb® C18 column (4.6×150mm) (Waters, Milford, MA) for DEHP and a 5�m Waters Symmetry® C18 column (4.6×150mm) (Waters, Milford, MA) for TOTM operatingeach at 20�2 °C. During assay development,DEHP and TOTM were eluted isocratically witha mobile phase consisting of acetonitrile-aqueousbuffer (triethylamine 0.08% adjusted to pH 2.8with phosphoric acid 1 M) mixture (88:12,v/v) ata flow-rate of 1.0 ml/mn and acetonitrile 100% at

a flow-rate of 1.2 ml/mn, respectively with a sys-tem back-pressure averaging �230 kPa. The mo-bile phase was filtered through a 0.45 �mmembrane and degassed under a helium streambefore use. The run time were 10 min and 15 minfor DEHP and TOTM, respectively.

2.4. Blood samples and extraction

Samples were directly collected on the haemodi-alysis line by sample site into heparinized glasstubes. Venous blood samples (5 ml) were drawnimmediately prior to dialysis, and then arterialand venous blood samples entering and leavingthe dialyzer were simultaneously obtained fromthe inlet and outlet tubing of the diayzer in thetwo groups study at 5, 15, 30, 60, 120, 180, 240min during the dialysis session and after centrifu-gation, plasma was frozen (−20 °C) into glasstubes until HPLC analysis.

2.5. DEHP plasma sample extraction

After defrosting, each plasma sample (1 mlaliquot) was spiked with 50 �l of DNHP (250 ng)as an internal standard in the glass tubes, fol-lowed by sodium hydroxide 1 M (1 ml), acetoni-trile (2 ml) and hexane (2 ml). The mixture wasstirred (5 min), centrifuged (1620×g for 5 min)and the separated organic layer (fraction 1) wastransferred to clean conical glass tubes. Theaqueous phase was extracted again with 2 ml ofhexane and the mixture was treated as above. Theseparated organic phase (fraction 2) was com-bined with fraction 1 and the total organic phasewas evaporated to dryness in a water-bath at40 °C under nitrogen. The residue was dissolvedin 100 �l of acetonitrile and after centrifugation,20 �l of the supernatant were finally injected intothe chromatograph.

2.6. TOTM plasma sample extraction

As for DEHP, TOTM quantification needs anextraction procedure before chromatographicanalysis.

Each plasma sample (1 ml aliquot) was spikedwith DNDP (2 �g) as an internal standard in the

K. Kambia et al. / International Journal of Pharmaceutics 229 (2001) 139–146142

glass tubes. Extraction was carried out in one stepby addition of sodium hydroxide 1 M (500 �l)followed by acetonitrile (1 ml) and hexane (3 ml).The mixture was stirred (5 min), centrifuged (1620g for 5 min) and the separated organic phase wasevaporated to dryness in a water-bath at 40 °Cunder nitrogen. The residue was dissolved in 100�l of acetonitrile and after centrifugation, 20 �l ofthe supernatant were finally injected into thechromatograph.

2.7. Quantitati�e determination

For DEHP or TOTM quantification, the peakarea ratio (DEHP/DNHP), or (TOTM/DNDP)(y) was calculated for each sample and theamount of DEHP or TOTM (x) was determinedusing the calibration curve ranged from 62.5 to4000 ng/ml and from 0.1 to 5 �g/ml respectively,obtained during the validation of methods. Meanlinear regression equations obtained were y=0.0046x+0.426 (r=0.999) for DEHP (five repli-cates) and y=0.61x−0.015 (r=0.999) forTOTM (seven replicates) with y, peak-ratiox, ana-lyte concentration ng/ml and �g/ml respectively.DEHP and DNHP or TOTM and DNDP werewell separated, identified and quantified by thisHPLC procedure and no co-extracted endogenouscompound exists at the retention times of bothDEHP and TOTM. The retention times were 6.60and 8.60 min for DNHP and DEHP, respectively;11.80 and 14.60 min for DNDP and TOTM,respectively. These methods had acceptable accu-racy and precision with intra-assay and inter-as-say coefficients of variation all below 5.2%, andthe recoveries for DEHP and TOTM were allbetter than 97%. The limit of quantification ofboth compounds was 25 ng/ml.

2.8. Serum biochemistry

Approximately 70% of the DEHP present inplasma stored in PVC bags is associated withlow-density and very low-density lipoproteins (Al-bro and Corbett, 1978). Thus, cholesterol andtriglycerides concentrations in serum were mea-sured to determine the influence of the aforemen-tioned serum constituents on the extraction ofDEHP or TOTM from dialysis tubing into blood.

2.9. Data analysis

The amounts of both DEHP and TOTM ex-tracted from haemodialysis tubing over a 4 h-dial-ysis session were estimated following transit ofblood through the dialyzer.

The amounts of DEHP or TOTM contaminat-ing the patient during dialysis session, Q wereobtained by calculating the AUCout (area underthe output dialyzer) concentration-time curve(venous line) and multiplied by the plasma flowrate D.

Q=D×AUCout.

The amounts of DEHP or TOTM retained by thepatient during the same period Q � were estimatedby calculating the difference between AUCout andAUCin for the area under the input dialyzer con-centration-time curve (arterial line) and multipliedby the plasma flow rate D.

Q �=D(AUCout−AUCin).

The area under the plasma concentration-timecurve (AUC) was calculated by trapezoidal rule.

3. Results and discussion

Fig. 1 shows DEHP and TOTM concentrationstime-course obtained from one haemodialysis pa-tient at the inlet and outlet of the dialyzer duringa 4 h-dialysis session. At the beginning of thetreatment, detectable concentrations of TOTM(�0.7 �g/ml) and DEHP (�0.1 �g/ml) werefound in all the blood samples. This observationis consistent with the fact that both plasticizersmight accumulate in patients undergoing regulartreatment resulting from the plasticizer redistribu-tion in the body due to lipophilic characteristics.The present study provides quantitatives data onthe concentrations of DEHP and TOTM in thearterial and venous blood tubes of 20 patients. InFig. 2, plasma DEHP concentrations of the group1 patients undergoing 4 h-dialysis sessions in-creased while for the group 2 patients, slightincrease was observed. The tubes plasticized withTOTM-DEHP show a low and constant leacha-bility of TOTM. So, with the blood lines used in

K. Kambia et al. / International Journal of Pharmaceutics 229 (2001) 139–146 143

Fig. 1. Time-course of DEHP and TOTM plasma concentrations at the inlet and outlet of the dialyzer during dialysis session forone patient: (A) Kinetics of DEHP leachability when classic lines plasticized PVC-DEHP were used (group 1 patients). (B) Kineticsof DEHP leachability when lines plasticized PVC-TOTM/DEHP were used (group 2 patients). (C) Kinetics of TOTM leachabilitywhen lines plasticized PVC-TOTM/DEHP were used (group 2 patients).

Fig. 2. Comparative amounts of TOTM or DEHP retained by patients according plasticized tubing used (Significant difference oftotal DEHP input between PVC-DEHP tubing and PVC-TOTM/DEHP (P�0.01).

K. Kambia et al. / International Journal of Pharmaceutics 229 (2001) 139–146144

Table 1Total DEHP exposure, total DEHP input and plasma concentrations of cholesterol plus triglycerides in 10 dialyzed patients

DEHP retained (mg)Patients Plasma cholesterol+triglycerides (g/l)DEHP exposure (mg)

Group 1: Patients on maintenance haemodialysis with PVC-DEHP tubing33.00130.27 3.40142.722 3.98166.2112.5095.54 2.703

4 147.02 36.56 5.2117.19110.32 ND524.136 1.9855.0023.58145.76 3.807

121.488 31.75 ND30.28158.42 4.459

99.4310 21.35 3.2027.30�9.22122.95�33.94

ND, not determined.

the group 2 patients, less TOTM and DEHP wereapparently leached than with the blood lines usedin the group 1 patients. These findings are consis-tent with earlier reports suggesting that significantamounts of DEHP are introduced into the sys-temic circulation of patients undergoing haemodi-alysis with blood lines plasticized with DEHP(Pollack et al., 1985; Faouzi et al., 1999). Ourdata indicated that, there was a decrease ofDEHP released when using new lines plasicizedwith TOTM-DEHP. However, the estimated val-ues previously reported for DEHP exposureranged widely. Gibson et al. (1976) found a largerrange (from 9 to 150 mg per dialysis). Pollack etal. (1985) estimated that patients received 23.8–360 mg of DEHP during 4 h-dialysis session.Therefore, a high degree of interindividual vari-ability in total DEHP exposure was noted. Thesame observation was found in our study with arange of 55–166.21 mg and 37.55–49.20 mg ofDEHP with PVC-DEHP tubes and PVC-TOTM/DEHP tubes respectively, while TOTM leachabil-ity during the same session ranged from 47.60 to125.70 mg. The reason for this discrepancy be-tween these studies is not found, but it may bedue to variations in DEHP or TOTM content ofthe dialyzer tubing or to differences in the dialysisprotocol. Other factors such as lipid plasma con-tent could influence the extraction of both plasti-cizers and could explain these differences.

No significant correlation was statistically

found between the amount of DEHP or TOTMextracted during a dialysis session and the numberof years of the prior dialysis treatment. In con-trast, the released of both DEHP or TOTM waslinked to the sum of the serum cholesterol andtriglycerides concentrations (r2=0.75 for DEHP;r2=0.64 for TOTM).

In the present study, results obtained afterHPLC data analysis are summarized in Tables 1and 2. The comparative amounts of TOTM orDEHP retained by patients are shown in Fig. 2.

Assuming a three times a week-treatmentschedule, the average patient in the group 1 wouldbe yearly exposed to �19.20 g of DEHP (rangingfrom 8.6 to 25.93 g). In the same period, anaverage patient of the group 2 will be yearlyexposed to 6.5 g of DEHP and 11.70 g of TOTM(ranging from 5.86 to 7.70 g and 7.40 to 19.61 g)respectively. On the other hand, quantities of bothplasticizers retained by an average patient duringa single dialysis session was evaluated. Tables 1and 2 show a high degree of interpatient variabil-ity in both DEHP and TOTM retained. The meanquantity of DEHP retained by the group 1 pa-tients during a single dialysis session would be�27.30�9.22 mg, while in the group 2, 3.42�1.34 mg of DEHP and 4.87�2.60 mg of TOTMwould be retained by an average patient. Thequantities of DEHP retained by the group 2 pa-tients were �8 fold than for the group 1 patients.This data shows that in the group 2 patients, less

K. Kambia et al. / International Journal of Pharmaceutics 229 (2001) 139–146 145

Table 2Total TOTM and DEHP exposure, total TOTM and DEHP input and plasma concentrations of cholesterol plus triglycerides in 10dialyzed patients

Group 2 Patients on maintenance haemodialysis with PVC-TOTM/DEHP tubing

Patients TOTM exposureDEHP exposure DEHP retained TOTM retained Plasma cholesterol+triglycerides (g/l)(mg)(mg)

105.72 5.331 5.8039.68 5.802 37.74 47.60 2.05 5.00 3.103 39.54 65.16 3.33 7.60 4.21

125.70 6.6749.20 3.304 5.6037.555 74.50 2.17 10.00 5.21

54.77 2.496 2.8037.73 3.5850.82 3.7245.92 1.907 2.20

38.568 55.91 2.00 4.13 1.9947.009 88.22 5.50 2.05 3.81

82.73 2.9045.01 6.1010 3.6875.11�25.72 3.42�1.34 4.87�2.6041.80�4.47

TOTM is leached from dialysis tubing, moreoverit seems to reduce the leachability of DEHP.TOTM or DEHP retained by the patients mightbe certainly responsible for biological effects.Toxicity studies in animals have demonstrated anassociation between exposure to DEHP andchanges in hepatocellular structure and liver func-tions, testicular atrophy in rats and proliferationof peroxisomes in rodents (Isseman and Green,1990; Parmar et al., 1995; Doull et al., 1999).

In contrary, the investigations of Rathinam etal. (1990) on the toxicity of TOTM in rats afterintraperitoneal did not show any change in theactivities of hepatic enzymes. These studies areindicative of the safer toxicokinetic properties ofTOTM compared with DEHP. In the other hand,the amount of peroxisome induction in TOTM-treated rats is less than those treated with DEHP.In addition, the monoester effects attributed tomono-ethylhexyl phthalate (MEHP) as the mainmetabolite of DEHP, was not seen with TOTM(Hodgsson, 1987). The results of the present studyindicate that patients undergoing dialysis with thenew lines are less exposed to both DEHP andTOTM than with the classics lines. These findingsare consistent with earlier reports (Flaminio et al.,1988; Christensson et al., 1991). Therefore,TOTM can be recommended as an alternativeplasticizer to DEHP, but its possible toxicity to-

wards the humans body should be investigatedbefore it can be routinely used. As very littleinformation is available on the biological effectsof TOTM, a number of studies including toxicity,disposition and metabolism are needed before re-placing DEHP with TOTM.

References

Albro, P.W., Corbett, J.T., 1978. Distribution of di- andmono(ethylhexyl) phthalate in human plasma. Transfusion18, 750–755.

Bojes, H.K., Thurman, R.G., 1994. Peroxisome proliferatorsinhibit acyl CoA synthetase and stimulate protein kinase Cin vivo. Toxicol. Appl. Pharmacol. 126, 233–239.

Christensson, A., Ljunggren, L., Nilsson-Thorell, C., Arge, B.,Diehl, U., Hagstam, K.E., Lundberg, M., 1991. In vivocomparative evaluation of hemodialysis tubing plasticizedwith DEHP and TEHTM. Int. J. Artif. Org. 14, 407–410.

Dine, T., Luyckx, M., Cazin, M., Brunet, C., Goudaliez, F.,Cazin, J.C., 1991. Rapid determination by high perfor-mance liquid chromatography of di(2-ethylhexyl) phthalatein plasma stored in plastic bags. Biomed. Chromatogr. 5,94–97.

Doull, J., Cattley, R., Elcombe, C., Lake, B.G., Swenberg, J.,Wilkinson, C., Williams, G., Van Gemert, M., 1999. Acancer risk assessment of di(2-ethylhexyl) phthalate: Appli-cation of the New US EPA risk assessment guidelines.Regul. Toxicol. Pharmacol. 29, 327–357.

Faouzi, M.A., Dine, T., Luyckx, M., Brunet, C., Mallevais,M.L., Goudaliez, F., Gressier, B., Cazin, M., Kablan, J.,Cazin, J.C., 1995. Stability and plasticizer extraction of

K. Kambia et al. / International Journal of Pharmaceutics 229 (2001) 139–146146

miconazole injection added to infusion solutions andstored in polyvinyl chloride containers. J. Pharm. Biomed.Anal. 13, 1363–1372.

Faouzi, M.A., Dine, T., Gressier, B., Kambia, K., Luyckx,M., Pagniez, D., Brunet, C., Cazin, M., Belabed, A.,Cazin, J.C., 1999. Exposure of hemodialysis patient todi(2-ethylhexyl) phthalate. Int. J. Pharm. 180, 113–121.

Flaminio, L.M., De Angelis, L., Ferazza, M., Marinovich, M.,Galli, G., Galli, C.L., 1988. Leachability of a new plasti-cizer TEHTM from haemodialysis tubing. Int. J. Art. Org.11, 435–439.

Gibson, T.P., Briggs, W.A., Boone, B.J., 1976. Delivery ofdi(2-ethylhexyl) phthalate to patients during hemodialysis.J. Lab. Clin. Med. 87, 519–524.

Hodgsson, J.R., 1987. Results of peroxisome induction studieson TOTM and 2-ethylhexanol. Toxicol. Indust. Health 3,49–61.

Isseman, I., Green, S., 1990. Activation of a member of thesteroid hormone receptor superfamily by peroxisome pro-liferators. Nature 347, 645–650.

Kluwe, W.M., Haseman, J.K., Douglas, J.F., Huff, J.E., 1982.The carcinogenicity of dietary di(2-ethylhexyl) phthalate inFischer 344 rats and B6C3F mice. J. Toxicol. Environ.Health 10, 797–815.

Martis, L., Freid, E., Woods, E., 1987. Tissue distribution andexcretion of TEHTM in rats. J. Toxicol. Environ. Health20, 357–366.

Nassberger, L., Arbin, A., O� stelius, J., 1987. Exposure ofpatients to phthaltes from polyvinyl chloride tubes andbags during dialysis. Nephron 45, 286–290.

Parmar, D., Srivastava, S.P., Singh, G., Seth, P.K., 1995.Testicular toxicity of di(2-ethylhexyl) phthalate in develop-ing rats. Vet. Human. Toxicol. 34, 310–313.

Peters, J.M., Taubeneck, M.W., Keen, C.L., Gonzalez, F.J.,1997. DEHP induces a functional zinc deficiency duringpregnancy and teratogenesis that is independant ofPPAR�. Teratol 56, 311–316.

Pollack, G.M., Buchanan, J.F., Slaughter, R.L., Kohli, R.K.,Shen, D.D., 1985. Circulating concentrations of di(2-ethyl-hexyl) phthalate and its de-esterified phthalic productsfollowing plasticizer exposure in patients receiving hemodi-alysis. Toxicol. Appl. Pharmacol. 79, 257–267.

Rathinam, K., 1988. Biotransformation of intravenously ad-ministered TEHTM in rabbits. Ind. J. Pharmacol. 19,149–150.

Rathinam, K., Srivastava, S.P., Seth, P.K., 1990. hepaticstudies of intraperitoneally administered TOTM andDEHP in rats. J. Appl. Toxicol. 10, 39–41.

Reddy, J.K., Lalwani, N.D., 1984. Carcinogenesis by hepaticperoxisome proliferators: evaluation of the risk of hy-polipidemic drugs and industrial plasticizers to human.Crit. Rev. Toxicol. 12, 1–58.

Turner, V.S., Mitchell, S.G., Kang, S.K., Hawker, R.J., 1995.A comparative study of platelets stored in polyvinyl chlo-ride containers plasticized with butyryl trihexyl citrate ortriethylhexyl trimellilate. Vox. Sang. 69, 195–200.

Van Den Munckhof, R.J.M., Bosch, K.S., Frederiks, W.M.,1998. The different effects of the peroxisome proliferatorsclfibric acid and DEHP on the activities of peroxisomaloxidases in rat liver. Histochem. J. 30, 339–349.