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Description of key information

Cardiac sensitisation was tested in dogs primed with adrenaline. Positive response was observed at concentrations higher than 7.5% HFC 125

Additional information

Two available acute cardiac sensitisation studies with dogs are available for HFC 125.

In the first study (Hardy et al., 1992), 12 beagle dogs were primed with adrenaline and subsequently exposed via face mask to 7.5, 10, 15, 20, 25, 30% HFC 125 for 5 minutes. After the exposure period, a second adrenaline injection was performed and a further 5 minute monitoring period was carried out. ECG recording was carried out for each animal during the experiment. CFC-11 2 -2.5% v/v was used as a positive control. The result of the study showed that the concentration of HFC-125 at which 50% of exposed dogs gave positive response to cardiac sensitization between 10 and 15% for HFC-125. 7.5% was considered the NOAEC of the study.

In another study, 10% of a blend of trifluoromethane (HFC 23) and HFC 125 (HFC 23/HFC 125: 36.5/63.5%) was tested with a similar protocol. 1/6 exposed dogs showed a positive response (fatal cardiac fibrillation).