Propan-1-ol

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

(only 15 females/dose group, treatment of females from gestation day 1-19)

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Developmental Toxicology of Industrial Alcohols: A Summary of 13 Alcohols Administered by Inhaltion to Rats

Author:

Nelson B.K., Brightwell W.S., Krieg E.F. Jr.

Year:

1996

Bibliographic source:

Intl. Journal of Occupational Medicine, Immunology and Toxicology Vol 5 (1) 29

Reference 2

Reference Type:

publication

Title:

Developmental Toxicology of Industrial Alcohols: A summary of 13 Alcohols Administered by Inhalation to Rats

Author:

Nelson B.K., Brightwell W.S., Krieg E.F. Jr.

Year:

1990

Bibliographic source:

Toxicology and Industrial Health, Vol. 6, (3/4), 373-387

Reference 3

Reference Type:

publication

Title:

Teratogenicity of n-Propanol and Isopropanol Administered at High Inhalation Concentration to Rat

Author:

Nelson B.K., Brightwell W.S., MacKenzie-Taylor D.R., Khan A., Burg J.R.,Weigel W.W., Goad P.T

Year:

1988

Bibliographic source:

Fd Chem. Toxic. Vol . 26, (3) 247-254

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

(only 15 females/dose group, treatment of females from gestation day 1-19)

Principles of method if other than guideline:

The alcohols were administered by inhalation for 7 hours per day on gestation days 1-19 to groups of approximately 15 pregnant Sprague-Dawley rats. For developmental toxicology evaluations, dams were sacrificed on gestation day 20. Fetuses were serially removed, weighed, sexed, and examined for external malformations. The frequency of visceral malformations and variations was determined in one-half of the fetuses, and the frequency of skeletal deviations was determined in the other half.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Propan-1-ol

EC Number:

200-746-9

EC Name:

Propan-1-ol

Cas Number:

71-23-8

Molecular formula:

C3H8O

IUPAC Name:

propan-1-ol

Test material form:

liquid

Specific details on test material used for the study:

- Source: Matheson, Coleman, and Bell Manufacturing Chemists, Cincinnati, OH)
- Analytical purity: The purity of n-propanol, as measured by gas chromatography, was greater than that of the standard sample (102.1%). Infra-red spectra indicated that the purity of isopropanol was 97.6% (by vol.), with approximately 1% water detected .

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, MA
- Weight at study initiation: (P) Males: >300g g; Females (virgin): 176-200 g
- Housing: males were housed individually throughout study, females were housed 3/cage and individually after mating
- Diet: ad libitum,(except during exposure periods), NIH-07 rodent pellets (Zeigler Bros., Inc ., Gardner, PA)
- Water: ad libitum (except during exposure periods), tap water
- Acclimation: 1-2 weeks (animals were free of mycoplasma, Sendai virus and external parasites)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24+/-2
- Humidity (%): humidity was not controlled but was generally about 40% (range 20-70%)
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Vehicle:

other: air

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 0.5 m3 Hinner inhalation chambers (Charles Spengler and Associates, Cincinnati, OH)
- Air change rate: 1 air change per minute
- Air flow rate: 0.5 m3/min
- Chamber conditions: 50 +/- 10% humidity and 23.3-25.6°C
- System of generating particulates/aerosols: Greensmith impinger

Analytical verification of doses or concentrations:

yes

Remarks:

chamber concentrations were monitored continuously by infra-red analyser; additionally charcoal tube samples were collected from the chamber atmosphere for independent verification of chamber concentrations and analysed by NIOSH analyticla methods

Details on analytical verification of doses or concentrations:

TEST ATMOSPHERE
- Brief description of analytical method used: Using Miran 1A Infrared Analyzer attached to a strip chart recorder and charcoal tube analyses ()
- Time schedule for verification: hourly and daily means, range and time weighted average concentrations were calculated. For charcoal tube analyses, sampling times varied from 10 to 30 min with a rate of sampling of 10 samples/week. Periodically, samples were collected from the control chamber filtered room air, and these were of approximately 6 hr duration. These samples were independently analysed by NIOSH analytical methods 1401

RESULT: Actual concentrations measured were close to target concentrations with no more than 10% deviations.

Details on mating procedure:

Breeder males were mated individually over a four day period with unexposed virgin females (200-300g). Mating was confirmed by the presence of sperm plugs under the cages or by vaginal smears (gestation day 0). After breeding, females were housed individually until parturition.

Duration of treatment / exposure:

- Females (postmating): day 1-19 of gestation

Frequency of treatment:

7 h/day, daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

3 500 ppm (nominal)

Remarks:

nominal conc.

Doses / concentrations 2

Dose / conc.:

7 000 ppm (nominal)

Doses / concentrations 3

Dose / conc.:

10 000 ppm (nominal)

No. of animals per sex per dose:

females: 15

Control animals:

other: Yes (filtered air)

Details on study design:

After the termination of exposure, animals were left for a degassing period of 30 min in the exposure chambers

Examinations

Maternal examinations:

BODY WEIGHT: Yes
- Time schedule for examinations: daily for the first week of exposure, then weekly thereafter.

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes
- Time schedule for measurements: weekly, measurements on gestation days 0, 7, 14, and 20).

WATER CONSUMPTION: Yes
- Time schedule for measurements: weekly, measurements on gestation days 0, 7, 14, and 20).

ALCOHOL BLOOD LEVEL
- Number of animals: three young non pregnanat female rats were exposed for 1, 10 or 19 days.
- Concentration: 10,000 ppm
- Time schedule of examination: 5 min post termination of vapour generation
- Sampling: 5 ml blood from inferior vena cava (frozen in EDTA or heparin until analysis)
- Method of analysis: Sigma Ethyl Alcohol kit (no. 332-UV; Sigma Chemical Co.)

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Number of corpora lutea: Yes
- Number of early and middle resorptions: Yes
- Number of late resorptions: Yes
- Number of live foetuses: Yes

Fetal examinations:

After sacrifice of dams on day 20, fetuses were serially removed, weighed, sexed, and examined for external malformations. The frequency of visceral malformations and variations was determined in one-half of the fetuses, and the frequency of skeletal deviations (malformations and variations) was determined in the other half.

Statistics:

Maternal data: parametric (multivariate analysis with baseline as covariate) or non-parametric multivariate analyses followed where appropriate by a Kruskal-Wallis test with paired comparisons. For the comparisons of corpora lutea, Kruskal-Wallis test was used

Foetal data: Analysis of variance was used to compare fetal weights across groups by sex. Group comparisons of litter size, percentage of live litter, percentage of normal foetuses/litter and percentage of females/litter were made using the Kruskal-Wallis test. For skeletal and visceral malformations and variations, external malformations and abnormal foetuses, the numbers of litters with one or more of the variables of interest were compared between groups using Fisher's exact test. Significance levels were set at P<= 0.05 and the results tests were adjusted for multiple comparisons using Bonferroni technique when necessary.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
- 3500 ppm: reductions in maternal feed intake (10% below control values) which was however not statistically significant
- 7000 ppm: reductions in maternal feed intake in the last 2 weeks of gestation, but body weights were not affected
- 10000 ppm: reductions in maternal feed intake throughout gestation, reduced body weight gain seen only at the end of gestation,

Effect levels (maternal animals)

Dose descriptor:

NOAEC

Effect level:

17 460 mg/m³ air (nominal)

Basis for effect level:

other: maternal toxicity

Maternal abnormalities

Abnormalities:

no effects observed

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
See attachment below for detailed results

3000 ppm: no adverse effects observed
7000 ppm: body weights were significantly less than controls (see table 1 below), incidence of skeletal malformations (primarily rudimentary cervical ribs), significantly increased from controls
10000 ppm: body weights were significantly less than controls (see table 1 below), incidence of external malformations (ectrodactyly or missing tail, in at least 1/3 of the foetuses) significantly increased compared to controls, incidence of skeletal malformations (mostly rudimentary cervical ribs) significantly increased compared to controls, incidence of visceral malformations (primarily cardiovascular or urinary defects) significantly increased compared to controls, incidence of resorptions significantly increased compared to controls (3/15 litters totally resorbed; 57% resorptions/litter versus 6% in control resorptions/litter), incidence of live implants/litter significantly reduced compared to controls with 43% vs 94% in controls.

Overall, in order of increasing concentrations of n-propanol, the numbers of litters with skeletal or visceral malformations/number of litters examined were 5/15, 2/15, 9/15 and 12/12.

Effect levels (fetuses)

1

Dose descriptor:

NOAEC

Effect level:

8 730 mg/m³ air (nominal)

Basis for effect level:

other: Based on reduced fetal body weights and higher incidence of rudimentary cervical rips

2

Dose descriptor:

LOAEC

Effect level:

17 460 mg/m³ air (nominal)

Basis for effect level:

other: developmental toxicity

Fetal abnormalities

1

Abnormalities:

effects observed, treatment-related

Localisation:

other: body weights

Description (incidence and severity):

foetal body weights were sigificantly less than controls (dose groups 7000 and 10000 ppm)

2

Abnormalities:

effects observed, treatment-related

Localisation:

skeletal: rib

other: rudimentary cervical ribs

Description (incidence and severity):

dose group 7000 ppm and 10000 ppm

3

Abnormalities:

effects observed, treatment-related

Localisation:

external: limb

external: tail

other: ectrodactyly; missing tail

Description (incidence and severity):

Dose group 1000 ppm

4

Abnormalities:

effects observed, treatment-related

Localisation:

visceral/soft tissue: urinary

visceral/soft tissue: cardiovascular

Description (incidence and severity):

Dose group 10000 ppm

5

Abnormalities:

effects observed, treatment-related

Localisation:

other: resorptions

Description (incidence and severity):

significantly increased incidence of resorptions in dose group 10000 ppm

6

Abnormalities:

effects observed, treatment-related

Localisation:

other: live implants

Description (incidence and severity):

significantly reduced incidence of alive implants/litter in dose group 1000 ppm

Overall developmental toxicity

Developmental effects observed:

yes

Lowest effective dose / conc.:

17 460 mg/m³ air (nominal)

Treatment related:

yes

Relation to maternal toxicity:

not specified

Dose response relationship:

yes

Relevant for humans:

not specified

Any other information on results incl. tables

Table 1: Reproductive observations made at the time of caesarean section of rats exposed for 7 h/d to n- propanol

Parameter	0 ppm	3500 ppm	7000 ppm	10000 ppm
Number bred	16	15	15	15
Number pregnant	15	15	15	15
Mean no. of corpora lutea/dam	15.1	15.9	14.1	14.6
Mean no. of implants/dam	15.6	15.5	13.9	14.1
Implants resorbed/litter (%)	6	4	11	57*
Implants alive/litter (%)	94	96	89	43*
Mean foetal weights ± SD (g)
Female	3.16 ± 0.26	3.14 ± 0.33	2.6 ± 0.32*	1.7 + 0.25*
Male	3.33 ± 0.26	3.3 ± 0.34	2.77 ± 0.30 *	1.79 ± 0.29 *

* significantly different from controls (p= 0.05; Kruskal-Willis test for corpora lutea comparisons and ANOVA for foetal data

BLOOD CONCENTRATIONS

8 young female rats were treated with 10000 ppm of n-propanol. They were all completely narcotized at the end of the 7 hour exposure period. 3 were killed for blood analysis (see table 2 below). The remaining 5 were still under narcosis 90 min after exposure and were dead by the next morning

Table 2: Blood levels of n-propanol after exposure of groups of three non pregnant adult female and young rats by inhaltion for 7h/d for up to 19 days

	Blood levels (mg/dl) after
Concentration	1	10	19
3500	2.6 (2.4-3.1)	ND	ND
7000	4.2 (3.3-5.9)	4.9 (2.1-9.1)	4.3 (3.1-5.8)
10000*	6.6 (6.1 and 7.7)	-	-
10000**	164 (147-198)	-	-

* The third rat had a blood level of 66.5 which was assumed to be an error and was deleted

** Young rats weighing 110-120g were exposed to 10,000 ppm n-propanol

ND: not detectable