Determination of total and free mono-n-butyl phthalate in human urine samplesafter medication of a di-n-butyl phthalate containing capsule

Toxicology Letters 188 (2009) 33–37

F1陳筱惠指導醫師：顏宗海醫師

Introduction Phthalates:

Industrial compounds manufactured via esterification of phthalic acid (benzene-1,2-dicarboxylic acid) with an alcohol

Apply in a lot of products as plasticisers Diethyl phthalate (DEP) and Phthalates like di-n-

butyl phthalate (DnBP) coatings in medical drugs, 9000ug per capsule V.S. 1ug/kg b.w. as food consumption in the general population (100X)

Some phthalates and their metabolites are developmental toxicants (endocrine disrupting compounds, EDC) in rats and mice

Hypospadias, delayed testes descent or vaginal pouch development

The main biologically active metabolite of DnBP: free MnBP glucuronidation detoxification

A valid exposure assessment as basis for a risk assessment for “normal” exposure to DnBP and DiBP and high dose exposure to DnBP after medication

Methods 24h interval urine: 17 samples, 3 days

Voluntary co-workers of the Bavarian Health and Food Safety Authority and their children, 7 males (including 2 children) and 10 females (including 2 children), 9~59 year-old, 21~100 kg (mean 61 kg)

8:00am, a capsule of an herbal drug containing 3600ug of DnBP (over-the-counter herbal pharmaceutical preparation for curing colds containing eucalyptus, anise and peppermint oil)

Control: urine collected 24h before taking it

Spot urine: 175 samples 115 healthy people, 37 men and 78 women,

28~58 year-old, living in the area of Munich, a 9-month time period in the years 2007 and 2008 at random times

60 samples with unkown sex and age Stored at −20◦C until measurements

All subjects in the study: To refrain from alcoholic beverages and

medicinal drugs 2 days before and throughout the experiment

Not alcohol abuser or smokers Self-declaration of the volunteers as healthy

Chemicals Analysis of urine samples Sample preparation for total MnBP and

MiBP Quantitation of MnBP and MiBP

ResultsConversion rate: 78%

2X 2X

Free MnBP:14~200ug, 1~11%(median 4%) of total MnBP

Free MiBP: 9.8% samples, 4.5~11.1ug

Endocrine active

Daily urine amount: 1.5/2.1L

2X

Discussion Exposure assessment:

After the administration of 3600ug of DnBP within 24hr most of the applied dose was excreted with urine as MnBP

Good agreement with previously published studies

Estimation for half life of MnBP of about 6hr

Control exposure: 23ug 2248ug, 100X Conversion rate of DnBP to MnBP: 78% 69%

previously Median uptake of DnBP and DiBP:

Lower than previous data 1.5 L urine amount: no difference between study 1

and study 2 2.1L: study 2 > study 1

Maximum levels or 95th percentile: study 2 = 5X study 1

Spot urine at the time points around 2h after taking DnBP or DiBP

Therefor, only median or mean values should be used for a valid exposure.

Risk assessment: Free MnBP: 4% of total amount of MnBP

No difference between normal and high exposure Comparable ratio as previous report Lower than rat model; tolerable daily intake (TDI)

10ug/kg b.w. 20~30% of DnBP and DiBP may be transferred

to other unknown metabolites.

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