Evaluation of Plasma Polyethylene Glycol (PEG) Levels in a Healthy Adult Population

Polyethylene glycols (PEGs) are amphiphilic polymers that are used extensively in consumer products and PEGylated biotherapeutics. Although PEGs are considered biologically inert with a low toxicity, anti-PEG antibodies have been detected in patients receiving treatment with PEGylated biotherapeutics as well as in healthy individuals. Despite continual exposure in daily life, the prevalence of PEGs within the general population remains unclear. This study aimed to evaluate a healthy population for the presence of PEGs. A validated enzyme-linked immunosorbent assay (ELISA) platform was used to analyze 200 plasma samples from healthy adults for the presence of PEGs. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was also used to analyze the samples for the presence of four PEG analytes: PEG3350; PEG4000; PEG10000; and PEG2ru20K COOH, a 20 kDa PEG used to modify therapeutic proteins. The detection limit for PEG3350 calculated by extrapolation with linear regression was assumed to be 3.60 ng/mL. PEG levels above the lower limit of quantification (LLOQ) (21.6 ng/mL) were detected in 41 plasma samples, range 22.1-43.9 ng/mL, using the ELISA platform. None of the samples were found to contain detectable levels of PEG4000, PEG10000, or PEG2ru20K COOH. Following extrapolation, PEG3350 levels above the LLOQ (3.60 ng/mL) were detected in 154 plasma samples, range 3.69-46.0 ng/mL. Using an ELISA platform and HPLC-MS/MS analysis, PEGs were detected in the plasma of 77.4% of healthy adults. The findings are suggestive that expanding worldwide exposure to PEGs may have resulted in a much higher incidence of detectable plasma burdens of PEG than was previously realized.