1-methyl-2-pyrrolidone

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 January 1994 to 17 November 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Objective of study:

toxicokinetics

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPPTS 870.7485 (Metabolism and Pharmacokinetics)

Version / remarks:

absorption, distribution, metabolism, excretion study after intravenous, oral, dermal and inhalation exposure

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1-methyl-2-pyrrolidone

EC Number:

212-828-1

EC Name:

1-methyl-2-pyrrolidone

Cas Number:

872-50-4

Molecular formula:

C5H9NO

IUPAC Name:

1-methylpyrrolidin-2-one

Test material form:

liquid

Details on test material:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: BASF AG, from continuous production, tank No. 53
- Analytical purity: 99.8 %

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: under N2, to be protected from air
- Stability under test conditions: stability ensured by substance supplier

Specific details on test material used for the study:

- Name of test material (as cited in study report): Unlabelled NMP
- source: BASF Corporation
- analytical purity: 99.9 %

- Name of test material (as cited in study report): [2-14C] NMP
- source: NEN Research Product, USA
- specific
activity: 26.2 mCi/mmol
- radiochemical purity: 97.1 %

Radiolabelling:

yes

Test animals

Species:

rat

Strain:

other: Crl:CD BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Raleigh, North Carolina, USA
- Age at study initiation: 7 to 17 weeks
- Weight at study initiation: 195 to 275 g for males and 170 to 270 g for females
- Fasting period before study: 12 to 19 hours and during 6 h hours for inhalation exposure
- Housing: stainless stell, wire-mesh
- Individual metabolism cages: yes, Roth-type glass metabolism unit
- Diet: ad libitum; Purina Certified Rodent Chow #5002
- Water: ad libitum
- Acclimation period: 6 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 2
- Humidity (%): 50 ± 10
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

intravenous

Vehicle:

water

Details on exposure:

The dose was formulated such that each rat received at least 15 µCi of 14-C radioactivity. To achieve the desired specific activity for the dosed material, non-radiolabeled NMP was mixed with 14C-NMP in a solution of water. Volumes of doses were 0.2 mL for the intravenous dose.

For preconditioned rats, non-radiolabeled NMP was dissolved in a solution of water. The dose solution was administered at a nominal amount of ca. 1mL/animal.

Duration and frequency of treatment / exposure:

max. 96 hours

Doses / concentrations

Dose / conc.:

50 mg/kg bw/day

Remarks:

single intravenous

No. of animals per sex per dose / concentration:

4 males and 5 females

Control animals:

no

Details on study design:

- Dose selection rationale: The dose level of 50 mg/kg bw was chosen based on previous studies and the results from the pilot study.
- Rationale for animal assignment: Rats were selected based on weight uniformity.

Details on dosing and sampling:

PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
Intravenous exposure
- Tissues and body fluids sampled: urine, faeces, blood, plasma, serum and all guideline conform tissues, cage washes,
- Time and frequency of sampling for blood: 1, 3, 5 and 30 minutes and 1, 2, 4, 8, 12, 24, 36, 48, 72, and 96 hours postdose
- Time and frequency of sampling for urine and feces: 12, 24, 36, 48, 72 and 96 hours postdose

METABOLITE CHARACTERISATION STUDIES
- Tissues and body fluids sampled: urine, faeces
- Time and frequency of sampling: 96 hours
- From how many animals:: for urine; individual samples from 4 male and 5 female rats; for feces: pooled after radioactivity levels were determined for each individual sample
- Method type(s) for identification : HPLC-MS/MS

Statistics:

The statistical analyses of data involved the calculation of the mean and standard deviation of replicate samples. Statistical bias was controlled by the non-systematic collection of samples for pooling and drawing aliquots, and the number and size of the aliquots analyzed . Data are presented as mean ± standard deviation of 4-5 animals . Statistical comparisons between groups were conducted by using different methods, depending on the purpose of analysis . The t-test, paired t-test, or analysis of variance (ANOVA) with generalized linear models were used . Results were considered statistically significant at a probability of 0.05 .

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:

After a single intravenous exposure, initial mean plasma concentrations were 114 (F) and 194 (M) ppm of NMP and 287 (F) and 350 (M) ppm for total radioactivity after injection of radiolabelled NMP.

Details on distribution in tissues:

After a single intravenous exposure, the apparent volume of distribution was calculated to be between 0.7 and 1.8 L/kg. The highest residual concentrations were found in the main organs of metabolism and excretion, liver and kidney. No bioaccumulation occurred in any tissue.

Transfer into organs

Test no.:

#1

Transfer type:

other: intravenous application

Observation:

distinct transfer

Details on excretion:

24 h after intravenous exposure, the total radioactivity in the plasma dropped to approx. 1.5 % of the administered dose. No NMP was detected in blood after 24 h.

Mean elimination half-life:
2.4 to 3.3 h for NMP, somewhat higher for radioactivity with 4.9 to 5.3 h representing both NMP and metabolites.

Within 96 h, 82 to 87 % was excreted into the urine with more than 74 and 72 % after 24 h, 4 to 6 % appeared in the feces, 0.65 % was found in tissues.

75 and 81 % of total radioactivity administered was excreted as metabolites into the urine without detectable conjugation.

Toxicokinetic parameters

Toxicokinetic parameters 1

Test no.:

#1

Toxicokinetic parameters:

half-life 1st: 2.4 to 3.3 h for NMP after i.v exposure

Toxicokinetic parameters 2

Test no.:

#2

Toxicokinetic parameters:

half-life 2nd: 4.9 and 5.3 h for radioactivity (NMP + metabolites) after i.v. exposure

Toxicokinetic parameters 3

Test no.:

#3

Toxicokinetic parameters:

AUC: 0.334 to 0.158 mg*h/mL for NMP

Toxicokinetic parameters 4

Test no.:

#4

Toxicokinetic parameters:

AUC: 0.701 to 839 mg*h/mL for radioactivity

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

The primary metabolite was 1-methyl-5-OH-2-pyrrolidone representing 58 and 55 % of the dose applied. The amount of NMP was less than 5 %.

Any other information on results incl. tables

Total recovery of radioactivity was between 92 and 97 %. 

Applicant's summary and conclusion

Conclusions:

No bioaccumulation potential based on study results expected.

Executive summary:

In an intravenous pharmacokinetics and disposition study, NMP and 14C-radiolabeled NMP were administered to 4 male and 5 female rats at an application volume of 0.2 mL/animal and at a concentration of 50 mg/kg bw.

Each rat was placed into Roth-type glass metabolism cage (separate urine/feces collection). Rats were maintained ad libitum on ground Purina certified rodent chow and water. Blood samples were collected at 1, 3, 5 and 30 min and 1, 2, 4, 6, 8, 12, 24, 36, 48, 72 and 96 hours post dose. Urine and feces were collected at 12, 24, 36, 48, 72 and 96 hours post dose. Animals were killed about 96 h after application.

The following organs and tissue samples were obtained and weighed: heart, lungs, liver, kidneys, spleen, testes (or ovaries and uterus), brain, G .I. tract, thymus, femurs, urinary bladder, marrow, and samples of skin, muscle, and fat. The contents of the G.I. tract were removed and treated as separate samples. The femurs were excised for bone marrow collection. The residual carcass was weighed.

Unchanged NMP in plasma was analyzed by HPLC. Radioactivity of radiolabelled NMP was analyzed by means of liquid scintillation counting. Metabolites were analyzed by HPLC or mass spectrometry.

The total recovery of radioactivity was between 92 and 97 %.

Initial plasma concentration was 114 and 194 ppm of NMP and 287 and 350 ppm of radioactivity from the radiolabelled NMP.

After 24 h, the total radioactivity in the plasma dropped to approx. 1.5 % of the administered dose. No NMP was detected in blood after 24 h. Mean elimination half-life was between 2.4 to 3.3 h for NMP, and somewhat higher for radioactivity with 4.9 to 5.3 h representing both NMP and metabolites. Within 96 h, 82 to 87 % was excreted into the urine with more than 72 and 74 % after 24 h. 4 to 6 % appeared in the feces, 0.65 % was found in tissues. 75 and 81 % of total radioactivity administered was excreted as metabolites into the urine without detectable conjugation. The primary metabolite was 1-methyl-5-OH-2-pyrrolidone representing 58 and 55 % of the dose applied. The amount of NMP was less than 5 %.

The apparent volume of distribution was calculated to be between 0.7 and 1.8 L/kg. The highest residual concentrations were found in the main organs of metabolism and excretion, liver and kidney. No bioaccumulation occurred in any tissue.

After intravenous exposure, NMP is rapidly excreted with elimination half-life was 2.4 to 3.3 hours. NMP has no bioaccumulation potential. Once absorbed, NMP was distributed, metabolized and eliminated in the urine with negligible tissue residues remaining after 4-5 days post dose. The primary metabolite was 1-methyl-5-OH-2-pyrrolidone representing 58 and 55 % of the dose applied.