THE GUINEA-PIG MAXIMIZATION TEST - WITH A MULTIPLE-DOSE DESIGN

The guinea pig maximization test (GPMT) is usually performed with one moderately irritant induction dose of the allergen and gives a qualita tive assessment - hazard identification - of the allergenicity of the chemical. We refined the GPMT by applying a multiple dose design and u sed 30 guinea pigs in a test divided into a control group and 5 test g roups of 5 animals. Each group was treated with different induction co ncentrations of the allergens: formaldehyde, cinnamic aldehyde, propyl paraben, lidocaine, mercaptobenzothiazole or chlormethylisothiazolino ne/methylisothiazolinone. The test results were analysed using a logis tic multidose response model. The precision of the results depends onl y on the total number of animals, the dose design and the response pat tern. The maximal sensitization rate for a chemical was determined, an d the intracutaneous induction concentration that sensitized 50% of th e animals (EC(50)) (or another percentage) was estimated, Further stud ies are needed to prove the validity of this idea, However, improvemen ts in protocols for the GPMT are needed to reduce interlaboratory vari ability in results and to reduce the number of animals used for allerg enicity tests.