Phthalate exposure through medication.

Jul 23, 2009

Seckin E, H Fromme and W Völkel. 2009.  Determination of total and free mono-n-butyl phthalate in human urine samples after medication of a di-n-butyl phthalate containing capsule. Toxicology Letters 188:33-37.


A new study finds that a single tablet of an over-the-counter medication can raise the levels of phthalates in the body by 100 fold before being quickly eliminated.

The protective layer that coats the outside of drug capsules contains enough of a phthalate to drive levels in those taking the drugs above the daily intake limits designated by food regulatory agencies in Europe.

While the phthalate and its breakdown products leave the body within one to three days, longterm use could keep their levels elevated and raise the risk of health effects associated with the endocrine disruptors. Taking phthalates out of medicines would limit exposure, say the study's authors.

Phthalates soften plastics and are commonly found in toys; health and beauty products; and medical tubing, medications and other supplies. The chemicals find their way into the environment to taint drinking water and food, exposing humans and wildlife. They are suspected of interfering with hormonal systems.

Two types of phthalates DEP and DnBP are used in coating agents on medical drugs and capsules. Rodent studies show that DnBP is an endocrine disruptor capable of causing malformations and delayed development of reproductive organs.

But, people metabolize DnBPs differently from rodents. To determine main metabolites and their evacuation times in humans, a team of scientist from Bavarian Health and Food safety Authority measured the levels of DnBP metabolites in urine samples from volunteers who ate a single capsule of an over-the-counter herbal medicine. The capsule contained about 3,600 micrograms of DnBp. The label recommended three capsules per day for the treatment of cold symptoms.

The researchers collected the urine samples before – a normal exposure – and at set intervals after the capsules were eaten – the high-dose exposure. They analyzed and compared the samples for levels of DnBP degradation products and metabolites.

More than three quarters of the administered DnBP was measured within the first day. The DnBP metabolites were detected as early as 1 day after administration of the capsule and were mostly eliminated from the body by day 3.

Still, 20 to 30 percent of the phthalate was not accounted for and may have transformed into an unknown metabolite. Most of DnBP was secreted as the metabolite MnBP within 24 hours, suggesting the phthalate breaks down and leaves the body rather quickly. Even so, a single capsule coated with DnBP caused a 100-fold increase in the levels of DnBP as compared to the control samples.

The number of volunteers in this study was limited to17 adults and children. Therefore, larger population studies will be beneficial to confirm these findings.

Since eating a single capsule drove the DnBP levels in the volunteers above the European Food Safety Authority (EFSA) recommended tolerable daily intake, chronic exposure to DnBp through medication raises many health concerns. According to the investigators, removal of phthalates such as DnBP from medical drugs would be a good, preventive health measure.