N-(hydroxymethyl)acrylamide

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July 1998-December 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented and scientifically acceptable report conducted to GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Objective of study:

absorption

distribution

excretion

metabolism

Principles of method if other than guideline:

Administration of radioactive NMA to rats and mice followed measurement of absorption, distribution, metabolism and excretion. Air, urine and faeces were collected and assayed for radioactivity. Organs were isolated, weighed and radioactivity content determined. Urinary metabolites were assayed and haemoglobin adducts measured.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

N-(hydroxymethyl)acrylamide

EC Number:

213-103-2

EC Name:

N-(hydroxymethyl)acrylamide

Cas Number:

924-42-5

Molecular formula:

C4H7NO2

IUPAC Name:

N-(hydroxymethyl)acrylamide

Details on test material:

- Name of test material (as cited in study report): HMA (Hydroxymethyl acrylamide)
- Substance type: organic
- Physical state: solution
- Analytical purity: 98% pure NMA in water
- Impurities (identity and concentrations): not specified
- Isomers composition: not applicable
- Purity test date: not specified
- Lot/batch No.: 5597-62-03 RTI
- Expiration date of the lot/batch:
- Radiochemical purity (if radiolabelling): 100%
- Specific activity (if radiolabelling): 31 μCi/mg
- Locations of the label (if radiolabelling): methylol group
- Expiration date of radiochemical substance (if radiolabelling): not specified
- Stability under test conditions: stable
- Storage condition of test material: not specified
- Other:
Radio-labelled HMA (lot Number CT-9279-39), labelled with carbon-14 in the hydroxymethyl group, was synthesized at RTI. The radiochemical preparation was supplied as a solution in water containing 30 ppm 4-methoxyphenol as a stabilizer. A total of 2.35 mCi was divided equally among 5 ampules each containing about 1 mL of solution. The specific activity of this batch of (14C)NMA was 31 μCi/mg. A second batch of radio-labelled NMA (lot Number CT -9556-15) was synthesized at RTI and had a specific activity of 16 μCi/m. This material was supplied as a solution in water containing 30 ppm 4-methoxyphenol. A total of about 364 μCi was divided equally among 4 ampules.
The radiochemical purity of this material was analysed by HPLC. Following injection of (14C)NMA, the column effluent was collected in fractions. The radioactivity eluting in each fraction was measured by liquid scintillation spectrometry (LSS).

Radiolabelling:

yes

Remarks:

Methylol carbon

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Charles River Labs, Raleigh, NC, USA
- Age at study initiation: 61-75 days
- Weight at study initiation: 19-25 gms
- Fasting period before study: no
- Housing: metabolism cages
- Individual metabolism cages: yes
- Diet: ad libitum
- Watert: ad libitum
- Acclimation period: at least 1 week
IN-LIFE DATES: From: July 1998 To December 2000:

Administration / exposure

Route of administration:

other: oral gavage and intraperitoneal

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
VEHICLE
- Justification for use and choice of vehicle (if other than water): water
- Concentration in vehicle: 30 mg NMA/ml
- Amount of vehicle (if gavage): 5 ml/kg
HOMOGENEITY AND STABILITY OF TEST MATERIAL: stable solution

Duration and frequency of treatment / exposure:

Single gavage and single ip exposures

Doses / concentrations

Remarks:

Doses / Concentrations:
150 mg/kg NMA containing 0.88-8.1 μCi radiolabel in both exposure routes

No. of animals per sex per dose / concentration:

4 males

Control animals:

no

Positive control reference chemical:

No

Details on study design:

- Dose selection rationale: not specified
- Rationale for animal assignment (if not random): random

Details on dosing and sampling:

PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: urine, faeces, blood, adipose tissue,brain, epidymis, heart, kidney, liver, lung, muscle, fore-stomach, glandular stomach and cage washes
- Time and frequency of sampling: after 8, 24, 48 and 72 hours for excreta, tissues at sacrifice (72 hours)

METABOLITE CHARACTERISATION STUDIES
- Tissues and body fluids sampled: urine and red blood cells
- Time and frequency of sampling: after 8, 24, 48 and 72 hours
- From how many animals: 4 per dose, no pooling
- Method type(s) for identification: GC/MS/MS, NMR, HPLC, LSS
- Limits of detection and quantification: not specified

Statistics:

Mean and standard deviation

Results and discussion

Preliminary studies:

None

Main ADME results

Main ADME results 1

Type:

excretion

Results:

66-77% of radioactivity excreted in urine and CO2 after 72 hours.About 9% was excreted in the faeces.

Main ADME results 2

Type:

absorption

Results:

Well absorbed based on high percentage of NMA and CO2 recovered in breath and urine and very low recovery in the faeces.

Main ADME results 3

Type:

distribution

Results:

Blood contained the highest percentage of radioactivity, presumably as the haemoglobin adduct.

Main ADME results 4

Type:

metabolism

Results:

NMA reacts with glutathione to produce the glutathione adduct across the carbonyl group. No epoxide was found in this study.

Toxicokinetic / pharmacokinetic studies

Details on absorption:

Total excretion 72 hours after oral administration was 79.1±12.3%
42.9±34.6% in urine, 11±1.62% in CO2 and 24.9±22.1% in faeces
Total excretion 72 hours after ip administration was 86.7±4.7%
72.6±7.11% in urine, 9.8±1.12% in CO2 and 4.06±2.9% in faeces

Details on distribution in tissues:

All organs had a tissue to blood ratio of 0.25-0.56 with adipose and skin on the low end and spleen and kidney on the high end. 25% of the remaining dose was found in the blood.

Details on excretion:

Within 24 hours of administration by IP, 60±17% of the administered dose was excreted. For oral administration, 53±19% was excreted in the same period.

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

The mercapturate N-acetyl-S-(3-hydroxymethylamino-3-oxopropyl)cysteine, arising from direct conjugation of NMA with glutathione and subsequent metabolism, was the major urinary metabolite. It represented about 41 % of the urinary metabolites after intraperitoneal administration and about 45% of the urinary metabolites (not including parent) after oral administration.

Any other information on results incl. tables

Total Excretion of (14C)NMA

End of collection period	IP Injection			Oral Administration
	% of total dose			% of total dose
8 hours	33.2	±	24.2	25.0	±	21.6
24 hours	60.1	±	16.9	53.2	±	18.7
48 hours	71.6	±	17.1	61.8	±	16.3
72 hours	86.7	±	4.7	79.1	±	12.3

End of collection period	Percent of Dose Recovered for IP Adminsitration
	Urine			Breath Volatiles			CO2			Faeces
8 hours	26.3	±	24.0	0.01	±	0.00	6.56	±	0.65	-
24 hours	50.2	±	17.6	0.10	±	0.04	8.36	±	0.72	1.41	±	0.67
48 hours	59.7	±	18.0	0.19	±	0.12	9.26	±	0.94	2.52	±	1.05
72 hours	72.6	±	7.11	0.24	±	0.17	9.8	±	1.12	4.06	±	2.29
End of collection period	Percent of Dose Recovered for Oral Adminsitration
	Urine			Breath Volatiles			CO2			Faeces
8 hours	18.0	±	21.0	0.02	±	0.02	6.96	±	1.02	-
24 hours	27.8	±	31.4	0.13	±	0.07	9.00	±	0.88	16.3	±	18.4
48 hours	31.0	±	32.8	0.25	±	0.10	9.85	±	0.95	20.7	±	19.2
72 hours	42.9	±	34.6	0.33	±	0.11	11.0	±	1.62	24.9	±	22.1

Organ Distribution of (14C)NMA

Tissue	IP Injection			Oral Administration
	% of total dose			% of total dose
Adipose	0.29	±	0.19	0.15	±	0.06
Blood	0.17	±	0.14	0.91	±	0.09
Brain	0.10	±	0.001	0.09	±	0.01
Epididymis	0.02	±	0.00	0.02	±	0.00
Heart	0.04	±	0.01	0.03	±	0.01
Kidney	0.16	±	0.03	0.16	±	0.03
Liver	0.39	±	0.10	0.35	±	0.06
Lung	0.05	±	0.01	0.05	±	0.10
Muscle	1.89	±	0.18	1.69	±	0.16
Fore-stomach	0.01	±	0.00	0.01	±	0.00
Glandular stomach	0.03	±	0.00	0.02	±	0.01
Small intestine including contents	0.20	±	0.02	0.23	±	0.06
Cecum including contents	0.05	±	0.01	0.10	±	0.09
Large intestine including contents	0.06	±	0.02	0.06	±	0.06
Skin	0.56	±	0.1	0.44	±	0.07
Spleen	0.02	±	0.01	0.02	±	0.00
Testis	0.04	±	0.01	0.03	±	0.00
TOTAL	4.77	±	0.29	3.74	±	1.09

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): no bioaccumulation potential based on study results
NMA administered either intraperitoneally or by gavage to mice at 150 mg/kg was excreted primarily (68-77%) in urine and faeces. About 10% of the radioactivity was excreted as 14CO2 after either route. The high percent of the dose recovered in urine and as CO2 indicates that NMA is well absorbed after either route of administration. Less than 0.5% of the dose was recovered in volatile breath. NMA did not accumulate in any tissue sampled after either route. Less than 5% of the administered radioactivity remained in the tissues sampled 72 h after dosing. The mercapturate, N-acetyl-S-(3-hydroxymethylamino-3-oxopropyl)cysteine, arising from direct conjugation of NMA with glutathione and subsequent metabolism, was the major urinary metabolite. It represented about 41 % of the urinary metabolites after intraperitoneal administration and about 45% of the urinary metabolites·(not including parent) after oral administration. These percentages are similar to those reported by Sumner et a!.(1992) for the amount of mercapturate of acrylamide present in mouse (41%) urine after oral (50 mg/kg) administration.