Prop-2-yn-1-ol

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1990 - 1992

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Prop-2-yn-1-ol

EC Number:

203-471-2

EC Name:

Prop-2-yn-1-ol

Cas Number:

107-19-7

Molecular formula:

C3H4O

IUPAC Name:

prop-2-yn-1-ol

Details on test material:

Test substance:
- Name of test material (as cited in study report): Propargylalkohol Partie B 463, 2-Propin-1-ol, PA
- Analytical purity: 99.4 %
- Lot/batch No.: 477/88/R
- Expiration date of the lot/batch: no information
- Stability under test conditions: Stability was ensured for the period of the study under the specified storage conditions
- Storage condition of test material: refrigerator, under nitrogen
- Other: Date of manufacture: 21 November 1988, Test substance no. 88/969

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Male and female SPF-Wistar-rats/Chbb:THOM, supplied by Dr. K. Thomae GmbH, D-W7950 Biberach, Germany
- Age at study initiation: about 7 weeks
- Weight at study initiation: Males: appr. 250 g, Females: appr. 169 g
- Fasting period before study: no information
- Housing: During the period when the rats were not exposed they were housed singly in wire cages (type DK III of Becker, Castrop-Rauxel. Germany)
- Diet (e.g. ad libitum): KLIBA rat/mouse laboratory diet 24-343-4 10 mm pellets, Klingentalmühle AG, CH-4303 Kaiseraugst, Switzerland ad libitum. During exposure food and water were withdrawn.
- Water (e.g. ad libitum): tap water ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): fully air-conditioned rooms
- Photoperiod (hrs dark / hrs light): 06.00 - 18.00 hours light, 18.00 - 06.00 hours dark

Administration / exposure

Route of administration:

inhalation

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Remarks on MMAD:

MMAD / GSD: no data

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION

- Exposure apparatus: Glass-steel inhalation chamber, volume appr. 1.100 L
- Method of holding animals in test chamber: Animais were kept singly in wire cages
- Source and rate of air: see "Method of conditioning air"
- Method of conditioning air: After measurement of the air streams of the total conditioned supply air, one part of this air streams was branched off and directed to the chamber via a generator system. In test groups 2 and 3 additionally compressed air was taken.
In detail, the following experimental procedures were used:
Test group 0: In order to achieve a chamber temperature comparable to the other test groups, in test group 0 the partial stream of supply air was introduced to a heatable glass heat exchanger. The heat exchanger was constructed in the same way as the glass vaporizer used in group 1.
Test group 1: The generation was carried out in a heatable glass vaporizer with a downstream mixing unit
Test groups 2 and 3: The generation was carried out in a heatable glass vaporizer with a downstream mixing unit heatable glass container with a downstream mixing unit by means of a two component atomizer with compressed air and counterstreamwise to supply air 2. The warmed up air of test group 0 and the vapor/air mixture in test groups 1 to 3 were then mixed again with the overall stream and introduced to a whole-body exposure system (glass-steel inhalation chamber) with a volume of about 1.1 m³. In addition, the exposure system was connected to an exhaust air system.
- System of generating particulates/aerosols: see "Method of conditioning air"
- Temperature, humidity, pressure in air chamber: The total supply air, the exhaust air, pressure condition in the chambers, relative humidities, and chamber temperatures were measured continuously with a measuring system. They were partially regulated and checked against to the defined limit values. This system was also used to record the generator parameters (temperature and compressed air). The partial stream via the generator system was continuously measured with a rotameter and recorded once daily. The stream of dosed test substance was recorded once daily.
Test group 0: The exhaust air system was set lower than the supply air system (overpressure). This ensured that no laboratory air reached the control animais. Test groups 1 -3: The exhaust air system was set higher than the supply air System (negative pressure). This ensured that the laboratory was not cantaminated as the result of any leakages from the inhalation chambers.
- The following amounts of test substance, air and evaporation temperatures were set:
Test group 0
Substance [µl/h]: -; Evaporation temperature [°C]: 23.3 - 26.0; Supply air [m³/h]: 21.8 - 22.0 conditioned air 1*; Exhaust air [m³/h]: 20.7 - 21.0
Test group 1
Substance [µl/h]: 38 - 58; Evaporation temperature [°C]: 22.6 - 29.8; Supply air [m³/h]: 21.6 - 22.7 conditioned air 1*; Exhaust air [m³/h]: 22.3 - 23.3
Test group 2
Substance [µl/h]: 188 - 271; Evaporation temperature [°C]: 23.8 - 26.0; Supply air [m³/h]: 21.7 - 21.7 conditioned air 1*, 0.2 - 0.4 compressed air; Exhaust air [m³/h] 22.3 - 22.5
Test group 3
Substance [ml/h]: 1.1 - 1.6; Evaporation temperature [°C]: 23. 1 - 24.8; Supply air [m³/h]: 21.7 - 21.7 conditioned air 1*, 0 .3 - 0.4 compressed air; Exhaust air [m³/h]: 22.3 - 22.5
* conditioned air 1 = conditioned supply air




TEST ATMOSPHERE

The total supply air, the exhaust air, pressure condition in the chambers, relative humidities, and chamber temperatures were measured continuously with a measuring system. They were partially regulated and checked against to the defined limit values. This system was also used to record the generator parameters (temperature and compressed air). The partial stream via the generator system was continuously measured with a rotameter and recorded once daily. The stream of dosed test substance was recorded once daily.

Analytical investigation:
The nominal concentration was calculated from the mean of the supplied substance and the amount of the supply air.
The concentration in the inhalation chambers was monitored by means of a total hydrocarbon analyzer. The total hydrocarbon analyzer was calibrated with mixtures of the test substance and air that were generated in the inhalation chambers not containing animais according to the test group concentrations. The concentrations of the test groups were analyzed by gas chromatography after absorption of propargylalkohol in 2-Propanol. The gas chromatograph was calibrated with weighed amounts of the test substance.

Monitoring of the inhalation atmosphere:
Samples were taken from the animals breathing zones in the inhalation chambers on the days of exposure. The sampling was carried out intermittently.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Concentration monitoring with the total hydrocarbon analyzer (see also "details on inhalation exposure". A study mean with standard deviation was calculated from the daily means of the individual concentrations of test groups 1 - 3 obtained with the total hydrocarbons analyzer.
The following study means were obtained:
Test group 1
Target concentration [ppm] 1.0; Analytical concentration ± standard deviation [ppm] 1.1 ± 0.17; Nominal concentration [ppm] 1.0
Test group 2
Target concentration [ppm] 5.0; Analytical concentration ± standard deviation [ppm] 5.1 ± 0.53; Nominal concentration [ppm] 4.5
Test group 3
Target concentration [ppm] 25.0; Analytical concentration ± standard deviation [ppm] 24.6 ± 2.15; Nominal concentration [ppm] 24.4

Duration of treatment / exposure:

90 days

Frequency of treatment:

6 hours/day, 5 days/week

Doses / concentrations

Remarks:

Doses / Concentrations:
0.002, 0.011, 0.058 mg/l (1, 5, 25 ppm)
Basis:
nominal conc.

No. of animals per sex per dose:

10 animals / sex / dose

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale:
Under the conditions of a 14-day dose finding study (Project No. 3610969/88060), inhalation of Propargyl alcohol by rats caused concentration-dependent liver damage in the form of hypertrophy of the liver cells and single cell necroses (at 200 ppm) and, due to an irritating effect, changes to the respiratory epithelial cells of the nasal mucosa in the form of inflammatory processes (purulent rhinitis at 200 ppm) as well as metaplastic changes (50 and 200 ppm). Body weight changes (50 and 200 ppm) and affected clinicochemical parameters (200 ppm) were associated with these lesions. 25 ppm was chosen as the highest concentration. In this concentration toxic effect should still be detectable. 5 ppm was chosen as the intermediate concentration to achieve a dose-effect relationship. 1 ppm was chosen as the low concentration. This should represent a NOEL.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes, see DETAILED CLINICAL OBSERVATIONS:


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: The behavior and state of health of the test animals were checked an workdays at least 3 times on exposure days and, as a rule, once during the preflow period and the post-exposure observation day.
- Lethality: A check for dead animais was made daily.


BODY WEIGHT: Yes
- Time schedule for examinations: The body weight of the animais was checked at the beginning of the exposure period, one day before beginning of the exposure period and then, as a rule, once a week. Body weight change: The difference between the body weight on the day of weighing and the body weight on the day before the first exposure was calculated as a group mean. This value was defined as body weight change.


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations and examined dose groups: At the beginning of the preflow period (day -10 (males), day -11 (females)) the eyes of all animals and at the end of the study (day 93), the eyes of the animals of test group 0 (control group) and of test group 3 (highest concentration) were examined with a focusable hand slit lamp (HEINE-Focalux hand slit lamp) for any changes to the refracting media.


HAEMATOLOGY: Yes
- Time schedule for collection of blood: Blood sampling after 94 days (Blood was taken from the retroorbital venous plexus in the morning from non-fasted, not anesthetized animals. The blood samplings and the subsequent analysis of the blood and serum samples were carried out in a randomized sequence. The list of randomization instructions was compiled with a computer using a random number generator.
- How many animals: Examinations were carried out in 10 animals per test group and sex.
- Parameters examined: WBC (Leukocyte count), RBC (Erythrocyte count), HGB (Hemoglobin), (HCT) Hematocrit, MCV (Mean corpuscular volume), MCH (Mean corpuscular hemoglobin), MCHC (Mean corpuscular hemoglobin concentration), PLT (Platelet count), Differential blood count, RETI (Reticulocytes), Clotting analysis (Thromboplastin time)


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Blood sampling after 94 days (Blood was taken from the retroorbital venous plexus in the morning from non-fasted, not anesthetized animals. The blood samplings and the subsequent analysis of the blood and serum samples were carried out in a randomized sequence. The list of randomization instructions was compiled with a computer using a random number generator.
- No. of animals examind: 10 animals per test group and sex.
- Parameters examined:
Enzymes: ALT (alanine aminotransferase), AST (aspartate aminotransferase), ALP (alkaline phosphatase), SCHE (serum cholinesterase), ECHE (erythocyte cholinesterase), GGT (serum-gamma-glutamyltransferase)
Blood chemistry: NA (sodium), K (potassium), CL (chloride), INP (inorganic phosphate), CA (calcium), UREA (urea), CREA (creatinine), GLUC (glucose), TBIL (total bilirubin), TPROT (total protein), ALB (albumin), GLOB (globulins), TRIG (triglycerides), CHOL (cholesterol), MG (magnesium)

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

The animais were sacrificed by exsanguination from the abdominal aorta and vena cava under Narcoren anesthesia. Then the animals were necropsied and assessed by gross pathology.
The weight of the anesthetized animals as well as the weight of liver, kidneys, adrenal glands, lungs and testes from all animais sacrificed at scheduled dates were determined. Subsequently, the following organs or tissues were fixed in 4% formaldehyde solution:
- all gross lesions - brain - pituitary gland - thyroid glands - parathyroid glands - thymus - trachea - lungs - heart - aorta - salivary glands (1) - liver - kidneys - adrenal glands - pancreas - uterus/vagina - accessory genital organs (2) - skin - esophagus - stomach - duodenum - jejunum - ileum - cecum - colon - rectum - urinary bladder - lymph nodes (3) - eyes - female mammary gland - sceletal muscle - sciatic nerve - sternum - bone marrow (femur) - spinal cord (4) - femur with articular surface - extraorbital lacrimal glands - nasopharyngeal tissues (5) - target organs
(1): mandibular glands (gl. mandibularis) and sublingual glands (gl. sublingualis)
(2): epididymides, prostate, seminal vesicle, coagulation gland
(3): mediastinal and mesenteric lymph nodes
(4): cervical, mid thoracic, lumbar cord
(5): head with nasal cavities und paranasal sinus

Other examinations:

none

Statistics:

The statistical evaluation of the data was carried out on the computer systems of the Department of Toxicology (no further details given).

Results and discussion

Results of examinations

Details on results:

CLINICAL SIGNS AND MORTALITY
During the preflow period the animals showed no clinical signs and findings different from normal.
Animal No. 55 (female) from test group 1 showed on days 31 - 51 alopecia in the region of thorax and stomach, scab formation being present between days 31 and 42. From day 52 onward until the end of the study (day 94) the fur regrew partly (sparse fur only). Animal No. 58 (female) from test group 1 showed as of day 39 alopecia on both forelimbs. This finding remained until the end of the study (day 94). All the other animals from the test groups 0 - 3 were without any clinical signs and findings. No deaths were recorded throughout the study.

BODY WEIGHT AND WEIGHT GAIN:
The body weight of the male and female animals of the test groups 1 to 3, compared to the control group 0, was not statistically significantly different. The body weight change of the male and female animals of the test groups 1 and 2 and of the females of the test group 3 compared to the control group 0 was statistically not significantly different. In the male animals of test group 3 there was on day 2 (p <= 0.01) and on day 9 (p <= 0.05) a statistically significantly retardation in body weight gain in comparison to the control group 0 (retardation on body weight gain during the first 2 weeks of the exposure period). Body weight of group 3 males remained somewhat lower compared with the other groups, but without a statistical significance after that period. This finding is assessed as a slight indication of a toxic effect.

OPHTHALMOSCOPIC EXAMINATION:
The ophthalmological examinations carried out with a hand slit lamp at the beginning of the preflow period and at the end of the study did not show any impairment of the refracting media.

HAEMATOLOGY:
No substance-induced changes.

CLINICAL CHEMISTRY:
At the end of the exposure period the cholinesterase activities in the serum of the female animals of test group 3 were statistically significantly decreased. Although this finding was not pronounced, the decrease in cholinesterase activity seen in the test group 3 females is assessed as being treatment-related and might be assigned to a slight impairment of liver function.
Statistically significantly decreased albumin concentrations were also found in the females of test groups 2 and 3 at the end of the exposure period. These findings, however, are not considered to be treatment-related, because the observed changes are marginal and the albumin levels of the females of test groups 2 and 3 (33.90 g/l each) were within the range of the historical controls of this parameter. Furthermore, no dose-response relationship was present in the test groups 2 and 3, although there was an increase in test substance concentration by a factor of about 5 and no corresponding changes were seen in the other sex. Thus, the statistically significant decrease in albumin concentration in the females of test groups 2 and 3 are regarded as incidental.

URINALYSIS: Not investigated.

NEUROBEHAVIOUR: Not investigated.

ORGAN WEIGHTS:
In determining the absolute and relative weights for the organs of both sexes the following statistically significant deviations were recorded:
The male animals of dose group 3 (25 ppm) showed an increase of the relative weight of the kidneys and the liver. Concerning the female animals, the absolute weights of the lungs (dose group 1; 1 ppm), of the adrenal glands (dose group 2; 5 ppm) and of the kidneys (dose group 3) were increased, as weIl as the relative weight of the kidneys in dose group 3.

GROSS PATHOLOGY:
The most obvious findings were seen in the liver, consisting in a prominent acinar pattern and a light brown discoloration. The altered acinar pattern was found in one or two cases in each group (ten animals each) with the exception of the females of dose groups 2 and 3. There was no dose-related distribution. Concerning the discoloration, only male animals were affected. There were 4 cases in the control group, 5 in group 1, 8 in group 2, and 9 in group 3. The other macroscopic findings represented spontaneous alterations without any relevance to the toxicopathological assessment of the test substance.

HISTOPATHOLOGY: NON-NEOPLASTIC
Nearly every male animal and about half of the females exhibited a fatty degeneration in the liver (males: 9 cases in the control group, 8 in group 1, 10 in group 2, and 10 in group 3; females: 5 in the control group, 5 in group 1, 4 in group 2, and 1 in group 3). The alteration showed a varying intensity, ranging from minimal to moderate (animals Nos. 9, 10, 16, 21, 22) without any dose-related distribution. The special staining of the liver of 5 animals of the control group and of the high dose group confirmed that the glycogen content in the hepatocytes was negligible.
The nasal cavities and the trachea showed no pathological alteration. In addition to same solitary areas of emphysema, osseus metaplasia and a bronchio-alveolar hyperplasia a lot of animals had focal infiltrates in the lungs. These predominantly mononuclear cells were seen in the interstitium and aggregated in the perivascular space. Their extent was of an insignificant dimension. Atelectatic areas were found in most cases in the apical part of the lobes. They were focal, very small and showed no sign of any further cellular reaction. The distribution of the haemosiderosis of the mediastinal lymph node was not dose-related either.

HISTORICAL CONTROL DATA:
Albumin concentrations of untreated female Wistar rats

OTHER FINDINGS
There are same additional statistically significant inter-group differences in the results of the clinicochemnical and hematological data. These deviations are marginal and inconsistent, when compared with the other sex. Accordingly, these changes are considered to be of no toxicological significance.

Effect levels

Dose descriptor:

NOEC

Effect level:

11 mg/m³ air (nominal)

Sex:

male/female

Basis for effect level:

other: findings at 58 mg/m³: increased kidney (both sexes) and liver (male) weight; retarded body weight gain (males) during first 2 wks; decreased cholinesterase activity (females)

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

In a 90-day inhalation study with Propargyl alcohol none of the macroscopic and microscopic findings recorded can be related definitly to the administration of the test substance and regarded as a toxicological effect.

Inspite of this, the statistically significant increase of the absolute and relative kidney weight in females and of the relative kidney weight in males, each in the high dose group, seems to be related to the inhalation of the test article. But no cellular alteration was found, to help to explain the dose-related change of these data.

The statistically significant increase of the relative liver weight in dose group 3 (males) also seems to be related to the inhalation of the test article, although no distinct morphological alteration was detected.

Fatty change, described for the liver, could be noticed in both sexes. The intensity varied from minimal (grade 1) to moderate (grade 3) but without any specific dose-related distribution. The five animals graded with 3 were males only. Without taking the grading values into consideration, the male animals exhibited two times more a fatty change of the liver than the females. This seems to correlate in a way with the macroscopically seen light brown discoloration, which can be interpreted as a sign of a higher portion of fat in the organ. Despite of this sex related difference it has to be pointed out that there was no significant alteration in size, concerning the hepatocytes.

Regarding the respiratory system, none of the findings reported are considered a specific effect. Mononuclear aggregates, for instance, are observed not only in old rats, but also as a physiological event in younger animals. The increase of the aggregates in size has to be regarded as an unspecific reaction and not as a consequence of the test substance properties themselves. The atelectatic areas represent an artefact, evoked by the collapse of the parenchyma during necropsy and the incomplete filling with the fixative.

All the other macroscopically and microscopically detected alterations are of spontameous nature without any toxicological relevance.

Applicant's summary and conclusion

Executive summary:

In a subchronic inhalation toxicity study Propargyl alcohol was administered to 10 Wistar rats/sex/concentration by whole body exposure at concentrations of 0.1 ppm (0.002 mg/L), 5 ppm (0.011 mg/L), 25 ppm (0.058 mg/L) for 6 hours per day, 5 days/week for a total of 90 days (65 exposures). At 5 and 1 ppm no treatment-related effects were observed. In the males of the 25 ppm group the body weight gain was retarded especially during the first 2 weeks of exposure; the relative kidney and liver weights were increased. In females the absolute and relative kidney weights were increased and cholinesterase activity was decreased. No further treatment-related effects were found regarding clinical and opthalmological examinations, hematology, clotting time analysis and clinicochemical analysis; especially no morphological and no histopathological findings were found which could be related to the observed effects. Based on the results, the NOEC is 5 ppm (0.011 mg/L). This subchronic inhalation toxicity study in the rat is acceptable and satisfies in general the guideline requirement for a subchronic inhalation study OECD 413 in the rat.