Variation in allergen content over time of acrylates/methacrylates in patch test preparations

Abstract

SummaryBackground Acrylates ⁄methacrylates are volatile substances. There might be a gradual decrease in acrylate ⁄methacrylate allergen content over time in patch test preparations but this has not yet been documented. Objectives To determine the allergen content of acrylates ⁄methacrylates in patch test preparations over time under different storage conditions. Methods Five acrylate ⁄methacrylate allergens [2-hydroxyethyl methacrylate (2-HEMA), methyl methacrylate (MMA), ethylene glycol dimethacrylate (EGDMA), triethylene glycol diacrylate (TREGDA) and 2-hydroxypropyl acrylate (2-HPA)] in syringes and IQÔ chambers (Chemotechnique Diagnostics, Vellinge, Sweden) were analysed using gel permeation chromatography and high-performance liquid chromatography to measure the allergen content over time in samples stored in the freezer, refrigerator and under room temperature. Results The concentration of allergens in syringes decreased with time. Those stored at room temperature had the fastest rate of decrease, followed by those in the refrigerator and freezer. In most cases, in syringes or IQÔ chambers under all storage conditions, the MMA decreased most rapidly, followed by 2-HPA, 2-HEMA, EGDMA and TREGDA. The allergens in the IQÔ chambers rapidly disappeared, with almost all samples reaching nondetectable levels by day 8. MMA was the first to reach a nondetectable level -at day 2. Conclusions Acrylate ⁄methacrylate allergens are lost rapidly from IQÔ chambers especially if stored at room temperature. Allergens in syringes remain above 80% of their initial concentrations for longer periods compared with IQÔ chambers. In syringes and IQÔ chambers there is a slower rate of decrease in concentration when the storage temperature is lower. Allergens should be stored refrigerated, replaced regularly, and freshly applied on to test patches on the day of use.

Stability of Patch Test Allergens

“…9 This same study showed that, when stored in IQ chambers, the concentration dropped to less than 80% of initial concentration by 1 day if stored at room temperature and by 2 days if refrigerated. One study showed that the compound is stable for up to 256 days when stored in polypropylene syringes in either a refrigerator or a freezer but not if stored at room temperature.…”

“…It was shown to be stable for up to 325 days when stored in polypropylene syringes in a refrigerator or a freezer. 9 When stored in IQ or IQ Ultimate chambers, the concentration of 2-HPA decreased to less than 80% of initial concentration by 72 hours if refrigerated and by 8 hours when kept at room temperature. When the syringes were stored in room temperature, the concentration decreased to less than 80% initial concentration by 21 days.…”

“…9 When stored in IQ or IQ Ultimate chambers, the concentration of 2-HPA decreased to less than 80% of initial concentration by 72 hours if refrigerated and by 8 hours when kept at room temperature. 9 However, the concentration of EGDMA drops to less than 80% of stated concentration within 1 day when stored in IQ chambers at room temperature and within 2 days when refrigerated in IQ chambers. 5 When concentrations of commercial samples of 2-HPA that had been used for routine patch testing at dermatology clinics were measured, all expired samples and 2 of the 3 nonexpired samples had less than 80% of the stated concentration.…”

“…5 When stored in Van der Bend transport containers, the compound was unstable by 7 days when refrigerated and by 48 hours when kept at room temperature. 9 In a second study, commercial EGDMA samples that were routinely used for patch testing at 9 dermatology departments were found to have 80% or greater of the stated concentration regardless of expiration date. 10 Ethylene glycol dimethacrylate (EGDMA) has been shown to be stable for up to 256 days when stored in polypropylene syringes in a freezer, in a refrigerator, or at room temperature.…”

“…9 However, all other analyses have documented it to be unstable. It was shown to be stable for up to 325 days when stored in polypropylene syringes in a refrigerator or a freezer.…”