Analysis of 19 preservatives in Polyvinyl Alcohol Cooling Towels Used in Japan by High Performance Liquid Chromatography with Photo Diode Array Detector

The cases of contact dermatitis due to using polyvinyl alcohol (PVA) towel containing isothiazolinone preservatives have been reported in Japan and we had investigated the concentrations of isothiazolinones and the removal of these preservatives from PVA towels by washing before initial use in the previous study conducted from 2011 to 2012. However, the clinical information regarding contact dermatitis due to using PVA cooling towels containing other preservatives was provided from the supplier of PVA towel in the summer of 2013. Thus, we analyzed 19 preservatives in 21 PVA towels by high performance liquid chromatography with photo diode array detector in this study. A good separation of these preservatives was observed using InertSustain® Phenyl column and 0.1 % formic acid solution as the mobile phase. 2-Methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4isothiazolin-3-one were detected in 16 samples, including the sample which was sold in a dry condition; the concentrations of these substances ranged from 7.9-84 μg/g-wet and 9.5-173 μg/g-wet, respectively (2.9 μg/g-dry and 9.3 μg/g-dry, respectively). 2-n-Octyl-4-isothiazolin-3-one was detected in one sample (484 μg/g-wet). 2Bromo-2-nitropropane-1,3-diol (BP) was detected in 15 samples, including the sample which was sold in a dry condition; its concentration ranged from 68-2303 μg/g-wet (160 μg/g-dry). 2-Phenoxyethanol (PE) and benzoic acid (BA) were detected in 3 and 2 samples, and their concentrations ranged from 99-3171 μg/g-wet and 1896-23043 μg/g-wet. Other preservatives were not detected. Although isothiazolinone preservatives were detected in 17 samples, the product notes of 10 products, including the product with clinical information, did not describe about the use of isothiazolinone preservatives. Since PVA cooling towels in contact with human skin for a long time, the PVA cooling towels should be used with caution, especially on patients who are already sensitive to isothiazolinone preservatives. Furthermore, we evaluated the effectiveness of the washing process on the removal of BP, PE, and BA from the PVA towels before their initial use. The results of this laboratory-simulated washing procedure suggest that contact dermatitis is likely not related to the presence of BP, PE, and BA in washed PVA towels.