Correlation between Stated and Measured Concentrations of Acrylate and Methacrylate Allergens in Patch-Test Preparations

Stability of Patch Test Allergens

“…5 When stored in Van der Bend transport containers, 2-HEMA is stable for up to 7 days at both room temperature and in a refrigerator. 10 Three of the 4 nonexpired samples, all of the expired samples, and all samples with unknown expiration dates had greater than 80% of the stated concentration, indicating stability of this compound. 3 Finally, samples of 2-HEMA that were routinely used for patch testing at several dermatology departments were analyzed.…”

“…5 A third study suggests stability of 2-HEMA (with slight increase in concentration) when stored in Van der Bend transport chambers in room temperature or in a refrigerator for up to 8 days. 10 These samples were refrigerated in syringes when not in use. 10 Three of the 4 nonexpired samples, all of the expired samples, and all samples with unknown expiration dates had greater than 80% of the stated concentration, indicating stability of this compound.…”

“…9 The same study also showed that 2-HPA was unstable in as little as one day when stored in IQ chambers in a refrigerator or at room temperature. 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. 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.…”

“…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. 10 These samples were refrigerated in syringes when not in use. 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.…”

“…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. 10 Methylmethacrylate (MMA) has been shown to be unstable by several groups. 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.…”