Day 28: same procedure as induction phase except 5% w/v test substance in mineral oil was applied to a previously non treated site. 2nd challenge: Day 35: same procedure as for 1st challenge except previously non exposed naïve animals were used. Grading of dermal responses occurred 24 and 48 hours post exposure. Challenge outcome: 1st challenge - number of animals exhibiting positive responses: Test Animals Naïve Control Animals 1st Challenge Concentration 24 hoursT 48 hoursT 24 hoursT 48 hoursT 5% 9*/19 10*/19 7*/10 8*/10 10**/19 9**/19 3**/10 2**/10 T time after patch removal. * number of animals exhibiting Grade +/- reaction, slight, patchy erythema. ** number of animals exhibiting Grade 1 reaction, slight but confluent, or moderate patchy erythema. Test animals had a slightly greater incidence of Grade 1 Comment: reactions compared to the naïve control animals, suggesting that sensitisation may have been induced. To confirm these results a 2nd challenge was conducted 7 days later using the same test animals and challenge Ten non previously exposed naïve animals were also concurrently treated with the test substance. 2nd challenge - number of animals exhibiting positive responses: Test Animals Naïve Control Animals 2nd Challenge Concentration 24 hoursT 48 hoursT 24 hoursT 48 hoursT 5% 9*/19 11*/19 5*/10 3*/10 10**/19 7**/19 5**/10 7**/10 T time after patch removal. * number of animals exhibiting +/- reactions. ** number of animals exhibiting 1 reactions. Following rechallenge the incidence of 1 reactions was Comment: similar between test and control animals. The study authors concluded that sensitisation had not been induced.
Day 28: same procedure as induction phase except 5% w/v test substance in mineral oil was applied to a previously non treated site. 2nd challenge: Day 35: same procedure as for 1st challenge except previously non exposed naïve animals were used. Grading of dermal responses occurred 24 and 48 hours post exposure. Challenge outcome: 1st challenge - number of animals exhibiting positive responses: 1st Challenge Test Animals Naïve Control Animals Concentration 24 hoursT 48 hoursT 24 hoursT 48 hoursT 5% 9*/19 10**/19 10*/19 9**/19 7*/10 3**/10 8*/10 2**/10 T time after patch removal. * number of animals exhibiting Grade +/- reaction, slight, patchy erythema. ** number of animals exhibiting Grade 1 reaction, slight but confluent, or moderate patchy erythema. Comment: Test animals had a slightly greater incidence of Grade 1 reactions compared to the naïve control animals, suggesting that sensitisation may have been induced. To confirm these results a 2nd challenge was conducted 7 days later using the same test animals and challenge Ten non previously exposed naïve animals were also concurrently treated with the test substance. 2nd challenge - number of animals exhibiting positive responses: 2nd Challenge Test Animals Naïve Control Animals Concentration 24 hoursT 48 hoursT 24 hoursT 48 hoursT 5% 9*/19 10**/19 11*/19 7**/19 5*/10 5**/10 3*/10 7**/10 T time after patch removal. * number of animals exhibiting +/- reactions. ** number of animals exhibiting 1 reactions. Comment: Following rechallenge the incidence of 1 reactions was similar between test and control animals. The study authors concluded that sensitisation had not been induced.
NA844FR.docx