Stability of selected volatile contact allergens in different patch test chambers under different storage conditions

Background. Patch test preparations of volatile substances may evaporate during storage, thereby giving rise to reduced patch test concentrations. Objectives. To investigate the stability of selected acrylates/methacrylates and fragrance allergens in three different test chambers under different storage conditions. Methods. Petrolatum samples of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (2-HEMA), 2-hydroxypropyl acrylate (2-HPA), cinnamal and eugenol in patch test concentrations were stored in three different test chambers (IQ chamber T, IQ Ultimate T, and Van der Bend (R) transport container) at room temperature and in a refrigerator. The samples were analysed in triplicate with high-performance liquid chromatography. Results. The decrease in concentration was substantial for all five allergens under both storage conditions in IQ chamber T and IQ Ultimate T, with the exception of 2-HEMA during storage in the refrigerator. For these two chamber systems, the contact allergen concentration dropped below the stability limit in the following order: MMA, cinnamal, 2-HPA, eugenol, and 2-HEMA. In the Van der Bend (R) transport container, the contact allergens exhibited acceptable stability under both storage conditions, whereas MMA and 2-HPA required cool storage for maintenance of the limit. Conclusion. The Van der Bend (R) transport container was the best device for storage of samples of volatile contact allergens.