Phthalic acid ester

Esters of phthalic acid with low and high molecular weight alcohols. Phthalic acid esters are water-insoluble, hardly volatile substances which have found a wide range of industrial and medical applications.

Phthalic acid esters are widely used as plasticisers for plastics. The relatively hard plastic polyvinyl chloride (PVC) only acquires elastic, deformable properties through the addition of plasticizers. About 90% of industrial phthalate production goes into the manufacture of soft PVC.

The most common phthalates used in plastics are:

• DIDP (di-isodecyl-phthalate)
• DINP (Di-isononyl-phthalate)
• DEHP (di(2-ethylhexyl) phthalate)
• DBP (Dibutylphthalate)
• BBP (Benzyl butyl phthalate)
• DEP (diethyl phthalate).

Products with soft PVC are almost ubiquitous. For example in floor coverings, as imitation leather, in packaging, in shoes as well as in sports and leisure articles and many consumer goods. Many medical technology products - such as blood bags and infusion tubes - contain soft PVC. They are also found in electrical cables in roofing membranes, and phthalic acid esters, among others, are also used in perfumery as solvents and fixatives. Esters with higher molecular weight alcohols (e.g. dioctylphthalate = DOC) serve as ointment bases and suppository carrier mass.

Phthalates belong to the so-called semi-volatile organic compounds (SVOC). In contrast to volatile organic compounds(VOC), which are emitted from products over a shorter period of time, phthalates only emit very slowly, but permanently during product use. They then tend to attach themselves to particles, such as house dust particles. Phthalates are hardly broken down in the environment. They are transported in the house dust by air. There is a direct correlation between the occurrence of allergic asthma and the amount of phthalates in the air we breathe.

Humans ingest phthalates through food, inhaled air or through direct skin contact.

Toys and childcare articles pose a particular risk to infants and young children, as they can be absorbed orally by sucking on objects. In the meantime, the EU Commission has banned phthalates in baby articles and toys from 0.1% by mass.

When used in medical articles such as infusion bags and infusion tubes, phthalates can enter the bloodstream directly. A restriction on the use of DEHP in medical devices is under discussion.

Observations of elevated phthalate concentrations in children with atopic eczema are noteworthy. In these cases, the eczematized skin appears to be capable of higher absorption of the environmental phthalates.

In a prospective study of 629 mother-child pairs (LINA Study 2018), an association was found between the concentration of butylbenzylphthalate (BBP) and an increased risk of asthma in children. This association was related to the third trimester of pregnancy. Etiopathologically, an epigenetically induced modulation of genes involved in Th2-cell differentiation by BBP could play a role (Jahreis S et al. 2018)

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2. BfArM - Bundesinstitut für Arzneimittel und Medizinprodukte (2006): Recommendations of the BfArM to minimize the risk of medical devices containing DEHP.
3. BfR - Bundesinstitut für Risikobewertung (2005): Transition of phthalates from twist off lids to food. Health Assessment No. 042/2005 of the BfR of 11 October 2005.
4. BfR - Bundesinstitut für Risikobewertung (2006): Recommendation I "Plasticizer-containing high polymers". Status 1.4.2006. Database for plastics recommendations of the BfR.
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