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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
20 August 1997 to 26 August 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study protocol followed was essentially equivalent to that of OECD Guideline 429 and is otherwise directly comparable to a guideline study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Principles of method if other than guideline:
The method followed was that described in KIMBER I, HILTON J and WEISENBERGER C (1989) The murine local lymph node assay for identification of contact allergens: A preliminary evaluation of in situ measurement of lymphocyte proliferation Contact Dermatitis 21 215-220 and BASKETTER D.A. and SCHOLES E.W. (1992) Comparison of the local lymph node assay with the guinea-pig maximisation test for the detection of a range of contact allergens. Food and Chemical Toxicology 30, 65-69.
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): tetrahydrofuran- Substance type: intended use as a chemical intermediate- Physical state: clear, colorless liquid- Analytical purity: 99.9%- Lot No.: BN 786- Sample No.: 245-016A- Date received: 18 July 1997- Expiration date of the lot/batch: assumed to be stable for six months from receipt- Storage condition of test material: ca. 4 deg C in the dark

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA/Ca
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS- Source: Harlan UK Ltd., Oxon, England on 14 August 1997- Age at study initiation: approx. 6 to 8 weeks prior to dosing on Day 1- Weight at study initiation: 15.3 to 21.3 g- Housing: groups of 4 in plastic cages with sawdust bedding (Lignocell, RS Services, Northants)- Diet (ad libitum): standard rodent diet R&M1 SQC- Water (ad libitum): yes- Acclimation period: 6 days prior to allocation to the testENVIRONMENTAL CONDITIONS- Temperature (°C): 19-26 (controlled)- Humidity (%): 68-76 (not controlled)- Air changes (per hr): at least 10 - Photoperiod (hrs dark / hrs light): 12/12IN-LIFE DATES: From: 20 August 1997 To: 26 August 1997

Study design: in vivo (LLNA)

Vehicle:
other: absolute alcohol
Concentration:
10, 25 and 50% w/w
No. of animals per dose:
4
Details on study design:
ADMINISTRATION OF THE TEST MATERIAL Groups of 4 mice were treated at one of the three concentrations of the test substance with 50 microliters of the test substance (25 microliters/ear) using an automated micropipette for each of 3 consecutive days. The test material was spread over the entire dorsal surface of the ear using the tip of the pipette. A further group of 4 mice received vehicle alone in the same manner.TRITIATED THYMIDINE ADMINISTRATIONFive days following the first topical application of the test material, all mice were injected via the tail vein with 250 microliters of physiological saline containing 3H-methyl thymidine (80 microCuries/ml) giving a total dose of 20 microCuries to each mouse. The injection into the tail vein was carried out with the mice restrained in a hot box, using a plastic syringe and needle.OBSERVATIONS- Clinical: All animals were observed on a daily basis for signs of toxicity or of ill health. Ears were examined for signs of irritation.- Body weights: Recorded for each mouse on arrival, on Day 1 (prior to dosing) and prior to study termination (Day 6).TERMINAL PROCEDURES- Termination: Five hours following tritiated thymidine administration, mice were killed by carbon dioxide asphyxiation. Draining auricular lymph nodes were excised and pooled for each experimental group. Animals were then discarded and no further investigations were carried out.PREPARATION OF SINGLE CELL SUSPENSIONSPrepared by gentle mechanical disaggregation through a 200-mesh stainless steel gauze using the plunger of a syringe. Pooled local lymph node cells (LNC) were pelleted at 190 x g for 10 minutes, washed twice with 10 ml of physioloigcal saline, and resuspended in trichloroacetic acid (TCA: 5%).DETERMINATION OF TRITIATED THYMIDINE INCORPORATIONAfter an overnight incubation at 4 deg C with TCA, the precipitate was recovered by centrifugation, resuspended in 1 ml of TCA, and transferred to 10 ml of scintillation fluid. Tritiated thymidine incorporation was determined by scintillation counting. The proliferative response was expressed as radioactive disintegrations per minute (dpm) per lymph node (dpm/node) and as the ratio of tritiated thymidine incorporation into LNC of test nodes relative to that recorded for control nodes (test/control ratio).INTERPRETATION OF RESULTSThe test substance is regarded as a sensitizer if at least one concentration of the chemical results in a three-fold greater increase in tritiated thymidine incorporation compared to control values.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
mercaptobenzothiazole (CAS No 149-30-4)
Statistics:
Individual and mean values reported.

Results and discussion

Positive control results:
The sensitivity and reliability of the test system was checked periodically with 2-mercaptobenzothiazole (MBT) and hexyl cinnamic aldehyde (HCA). In 5 control studies conducted between 14 Dec 1995 and 26 March 1997, tests conducted with either MTB or HCA at concentrations of 10, 25 or 50 % (v/v) gave acceptable positive responses as indicated by a test/control ratios of 3.0 or greater.

In vivo (LLNA)

Results
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: The disintegrations/minute (DPM), DPM/node, and test/control ratios for each group were as follows:Control: 6231, 779, na10 % v/v: 3561, 445, 0.625% v/v: 4625, 578, 0.750% v/v: 4364, 546, 0.7

Any other information on results incl. tables

CLINICAL SIGNS

No signs of ill health or toxicity were recorded.

BODY WEIGHTS

Body weight increases were recorded for all groups of mice over the course of the study (Day 1 and last day of observation). There was no obvious effect of the test substance on body weights.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
A test/control ratio of greater than 3 was not recorded for any concentrations of the test substance. This negative response indicates that tetrahydrofuran does not have the potential to cause skin sensitization.