Registration Dossier

Administrative data

Endpoint:
specific investigations: other studies
Remarks:
Cardiac Sensitisation
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
24/06/2015 - 06/11/2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report Date:
2015

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
Study is designed to test the cardiac sensitisation to adrenaline challenge following inhalational exposure to the test substance.
GLP compliance:
yes (incl. certificate)
Type of method:
in vivo
Endpoint addressed:
other: Cardiac Sensitisation

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
gas

Test animals

Species:
dog
Strain:
Beagle
Sex:
male
Details on test animals and environmental conditions:
Naïve male Beagle dogs were used as the test system for this study. A total of 10 male Beagle dogs were received in good health from Ridglan Farms, Inc. Mt. Horeb, WI on 25-Jun-2015. Each animal was examined by a qualified technician on the day of receipt and weighed on the following day. Animals were uniquely identified by an ear tattoo provided by the supplier.

All animals were observed twice daily throughout the study (once in the morning and once in the afternoon) for mortality/moribundity and changes in general appearance or behavior.

During the pretreatment period, animals were acclimated to the muzzle-only exposure/restraint apparatus on 4 occasions in order to condition the animals to the test substance exposure conditions. The first 2 acclimation sessions were for 15 minutes (first session without mask), the third session for 30 minutes, and the fourth session for 45 minutes.

This species and breed of animal is recognized as an appropriate model for assessment of potential cardiac sensitization (Mullin et al., 1979; Reinhardt et al., 1971; ECETOC Technical Report No. 105, 2009). Use of 10 animals was required to ensure availability of a sufficient number of ECG-acceptable and restrainer-acclimated study animals (6 dogs placed on study).

The number of animals selected was the minimum needed to yield scientifically meaningful data. Only males were used as no significant gender difference was expected.

Animals were arbitrarily assigned to the study based on health (body weight and physical examination), temperament, and pre-test ECG results.

The animals were approximately 7 to 9months of age and individual body weights ranged from 8.4kg to 9.0kg at the initiation of dosing(test substance exposure).

Administration / exposure

Route of administration:
inhalation: gas
Vehicle:
unchanged (no vehicle)
Details on exposure:
All animals were exposed to the test substance using a muzzle-only exposure apparatus. Test substance exposure atmospheres were prepared in 200-L Tedlar® bags. A known volume of the test substance was diluted with sufficient air to achieve the appropriate target concentration for each exposure. Oxygen was supplemented as necessary to maintain a level of 19% O2 or above. The method of exposure was documented in the study records and is described in detail in the Exposure Atmosphere Generation Report (Appendix C). Food and water was withheld during the exposure period. The test atmosphere exposures were prepared at room temperature using dry compressed air.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Exposure concentrations in the Tedlar® bags were measured by gas chromatography prior to initiation and after completion of each exposure. Oxygen content of each exposure atmosphere was recorded prior to initiation of each exposure.
Duration of treatment / exposure:
10 minutes
Frequency of treatment:
Once
Post exposure period:
5 mins.
Doses / concentrationsopen allclose all
Dose / conc.:
147 478 mg/m³ air (analytical)
Dose / conc.:
24 285 ppm (analytical)
Dose / conc.:
309 555 mg/m³ air (analytical)
Dose / conc.:
50 974 ppm (analytical)
Dose / conc.:
459 104 mg/m³ air (analytical)
Dose / conc.:
75 600 ppm (analytical)
No. of animals per sex per dose:
6
Control animals:
yes, concurrent vehicle

Examinations

Examinations:
ECGs were recorded with a DSI PONEMAH system. Only modified lead II ECGs were collected. Alligator clips were placed on each limb. ECGs were recorded continuously throughout the pre-exposure epinephrine dosing, during exposure to the test substance, and for 5minutes following administration of the challenge epinephrine dose (total of approximately 17minutes). The points at which epinephrine was given and when exposure to the test substance was initiated were clearly marked on each ECG recording.

ECG recordings taken during exposure to the test substance and after administration of the challenge epinephrine dose were compared to the ECG recordings made after administration of the pre-exposure epinephrine dose that was given in the absence of test substance. The assessment of each ECG recording was performed by trained personnel.

During the epinephrine challenge (or immediately following), the following types of criteria (though not exclusive) were applied in order to determine if sensitization had occurred:

-Eleven or more PVCs (premature ventricular contraction) in 10 seconds, with episodes of confluency
-Ventricular tachycardia
-Fibrillation
Positive control:
N/A

Results and discussion

Details on results:
Following exposure to 147,478, 309,555 and 459,104 mg/m3 (24,285, 50,974 and 75,600 ppm respectively) HCFO-1224yd(Z), there were no signs of cardiac sensitization. There were no clinical observations of PVCs (premature ventricular contractions), ventricular tachycardia, or fibrillation noted during exposure to the test substance during this study. A single PVC was observed during the epinephrine pre-exposure period for male no. 7603 prior to exposure to 459,104 mg/m3 (75,000 ppm) HCFO-1224yd (Z).

Applicant's summary and conclusion

Conclusions:
A study was conducted to determine the cardiac sensitisation in response to administration of the test item by inhalation. Following exposure to 147,478, 309,555 and 459,104 mg/m3 (24,285, 50,974 and 75,600 ppm respectively) HCFO-1224yd(Z), there were no signs of cardiac sensitization. There were no clinical observations of PVCs (premature ventricular contractions), ventricular tachycardia, or fibrillation noted during exposure to the test substance during this study. A single PVC was observed during the epinephrine pre-exposure period for male no. 7603 prior to exposure to 459,104 mg/m3 (75,000 ppm) HCFO-1224yd (Z).

It was therefore determined that the test item does not cause cardiac sensitisation.
Executive summary:

A study was conducted to determine the cardiac sensitisation in response to administration of the test item by inhalation. Following exposure to 147,478, 309,555 and 459,104 mg/m3 (24,285, 50,974 and 75,600 ppm respectively) HCFO-1224yd(Z), there were no signs of cardiac sensitization.  There were no clinical observations of PVCs (premature ventricular contractions), ventricular tachycardia, or fibrillation noted during exposure to the test substance during this study. A single PVC was observed during the epinephrine pre-exposure period for male no. 7603 prior to exposure to 459,104 mg/m3 (75,000 ppm) HCFO-1224yd (Z).

It was therefore determined that the test item does not cause cardiac sensitisation.