Poor correlation between stated and found concentrations of diphenylmethane-4,4'-diisocyanate (4,4'-MDI) in petrolatum patch-test preparations.
Diphenylmethane diisocyanate (MDI) is widely used in its polymeric form in the manufacturing of polyurethane products. Previous reports on MDI-related contact allergy have shown a pattern, where patients seem to react to their own MDI-based work material but not to commercial patch-test preparations, which contain 4,4'-MDI. Therefore, we performed chemical analyses of 14 commercial test preparations of 4,4'-MDI obtained from 8 European and 4 American dermatology departments as well as 2 preparations from 2 major European suppliers of patch-test allergens. A new method for monitoring 4,4'-MDI in petrolatum preparations was developed and the determination of 4,4'-MDI as the MDI-dibutylamine derivative using liquid chromatography-mass spectrometry was performed. None of the preparations obtained from the dermatology departments contained more than 12% of the concentration stated on the label. In most cases, 4,4'-MDI content was only a few percentages or less of the concentration stated. 7 of the 14 preparations were analysed before the expiry date. Yet, only 1 of them, a preparation directly obtained from the supplier, came close to the concentration stated on the label. Thus, using these preparations, patients will be tested with a lower concentration than intended, leading to possible false-negative reactions.
Frick
Malin
M
Department of Occupational and Environmental Dermatology, Malmö University Hospital, Malmö, Sweden. malin.frick@skane.se
Zimerson
Erik
E
Karlsson
Daniel
D
Marand
Asa
A
Skarping
Gunnar
G
Isaksson
Marléne
M
Bruze
Magnus
M
D000485:Allergens / Q000737:chemistry*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis; D004643:Emollients / Q000737:chemistry*; D005188:False Negative Reactions; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D017953:Isocyanates / Q000032:analysis*; D010328:Patch Tests / Q000592:standards*; D010577:Petrolatum / Q000737:chemistry*; D001559:Benzhydryl Compounds
D000485:Allergens; D004643:Emollients; D017953:Isocyanates; D010577:Petrolatum; C005969:4,4'-diphenylmethane diisocyanate; D001559:Benzhydryl Compounds