Are contact allergens stable in patch test preparations? Investigation of the degradation of d‐limonene hydroperoxides in petrolatum

Abstract

Several of the products formed after oxidation of d-limonene exhibit strong contact allergenic properties. Some, e.g., the hydroperoxides, are unstable compounds. In this study, we have examined whether the limonene hydroperoxides are chemically stable in white petrolatum used for patch testing. We found that the stability of the hydroperoxides was strongly dependent on whether or not the petrolatum was stabilized with alpha-tocopheryl acetate. In the presence of this antioxidant, the hydroperoxides were degraded to a greater extent. The hydroperoxides were shown to be directly reduced to the corresponding alcohols by this agent. On the other hand, the compounds where shown to be stable in non-stabilized petrolatum throughout clinical patch testing for a period of 6 weeks, provided that the preparations were stored in a refrigerator when not used. Thus, it is recommended that vehicles without alpha-tocopheryl acetate are used when peroxy or hydroperoxy compounds are patch tested or used in sensitization experiments. However, it is important to limit the storage time so that optimal conditions are at hand. A fast method was developed to enable isolation and quantification of the hydroperoxides in white petrolatum. This analytical method may also be applicable to other compositions of patch test preparations.

Concentrations and stability of methyl methacrylate, glutaraldehyde, formaldehyde and nickel sulfate in commercial patch test allergen preparations

“…Regardless of the nature of the vehicle, the allergen must be sufficiently stable within that vehicle to deliver a consistent dose to the skin. Several studies have examined the stability of specific patch test allergens in pet., and have shown potential storage problems for some preparations . In the present study, we analysed the concentrations of the patch test preparations NiSO 4 , formaldehyde, glutaraldehyde and methyl methacrylate from both ‘in use’ in‐date and expired allergen preparations from three different patch test clinics.…”

Free radicals in antigen formation: reduction of contact allergic response to hydroperoxides by epidermal treatment with antioxidants

“…In this study we have used non‐stabilized petrolatum as a vehicle to prevent possible interference of the tocopherol in the vehicle. We have previously shown that the content of Lim‐OOH in stabilized petrolatum rapidly decreases, whereas it is stable in non‐stabilized petrolatum 14 …”

Vapor Pressure and Predicted Stability of American Contact Dermatitis Society Core Allergens

“…1 These studies are summarized in Table 1 and include thiurams, 2 p -toluene diamine, 3 diisocyanates, 12,16 limonene hydroperoxide, 13 fragrances, 14,15 triglycidyl isocyanurate, 11 methyldibromo glutaronitrile, 5 acrylates, 9,10 corticosteroids, 8 as well as other allergens. 4,6,7,10 Data from these studies and others suggest that allergen vapor pressure (VP) is one of several important factors in predicting allergen stability.…”