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Concentrations and stability of methyl methacrylate, glutaraldehyde, formaldehyde and nickel sulfate in commercial patch test allergen preparations
Author(s) -
Siegel Paul D.,
Fowler Joseph F.,
Law Brandon F.,
Warshaw Erin M.,
Taylor James S.
Publication year - 2014
Publication title -
contact dermatitis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 96
eISSN - 1600-0536
pISSN - 0105-1873
DOI - 10.1111/cod.12169
Subject(s) - glutaraldehyde , methyl methacrylate , formaldehyde , patch test , allergen , chemistry , chromatography , reagent , allergic contact dermatitis , nuclear chemistry , medicine , organic chemistry , allergy , immunology , copolymer , polymer
Summary Background Epicutaneous patch tests are used to reproduce allergy and diagnose allergic contact dermatitis. Reliable allergen test preparations are required. Objectives The purpose of the present study was to measure the actual concentrations of nickel( II ) sulfate hexahydrate ( NiSO 4 ), methyl methacrylate, formaldehyde, and glutaraldehyde, and to compare them with the labelled concentrations, in commercial patch test allergen preparations found in dermatology clinics where patch testing is routinely performed. Materials and methods The commercial in‐date and out‐of‐date patch test allergen preparations concentrations of NiSO 4 , methyl methacrylate, formaldehyde and glutaraldehyde from one to three participating clinics were analysed with chromatographic or wet chemical techniques. Results NiSO 4 and formaldehyde concentrations were at or above the labelled concentrations; however, formaldehyde loss occurred with storage. NiSO 4 particulate was uniformly distributed throughout the petrolatum. ‘In‐use’ methyl methacrylate reagent syringes all contained ≤ 56% of the 2% label concentration, with no observable relationship with expiration date. Lower methyl methacrylate cocentrations were consistently measured at the syringe tip end, suggesting loss resulting from methyl methacrylate's volatility. The concentrations of glutaraldehyde patch test allergen preparations ranged from 27% to 45% of the labelled (1% in pet.) concentration, independently of expiration date. Conclusions Some false‐negative methyl methacrylate, formaldehyde or glutaraldehyde patch test results may be attributable to instability of the test preparations.