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Diss Factsheets

Toxicological information

Basic toxicokinetics

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Administrative data

basic toxicokinetics in vivo
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference Type:

Materials and methods

Objective of study:
Principles of method if other than guideline:
The mechanism of the intestinal fat absorption has been studied with 14C labeled fat in rats with the intestinal lymph duct cannulated.
GLP compliance:

Test material

14C labeled fat

Test animals

not specified
not specified

Administration / exposure

Route of administration:
oral: gavage
Duration and frequency of treatment / exposure:
single oral exposure
(at least 18 hours after surgery)
Doses / concentrations
Doses / Concentrations:
A) 0.5 mL corn oil + 2.5 mg active palmitic acid-1-14C
B) 0.5 mL corn oil transesterified with 2.5 mg active palmitic acid-1-14C
C) 0.5 mL hydrolysed corn oil + 2.5 mg active palmitic acid-1-14C
No. of animals per sex per dose / concentration:
Control animals:

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:
24 hours after administration of the different fats the mean recovered activities in lymph were as following:
A) 0.5 mL corn oil + 2.5 mg active palmitic acid-1-14C: 57.0 %
B) 0.5 mL corn oil transesterified with 2.5 mg active palmitic acid-1-14C: 61.7 %
C) 0.5 mL hydrolysed corn oil + 2.5 mg active palmitic acid-1-14C: 62.3 %

In all three groups of experiments maximum recoveries were found after 24 hours, i.e. 80.9, 85.0 and 87.5 % of the activity given.
Free fatty acids administered alone or together with glycerides appear in the lymph in glycerides and phospholipids.
No free fatty acids or soaps appear in the lymph.
The intestinal wall supplies a quantitatively important part of phospholipids to the blood during fat absorption.
The recoveries in the lymph of the fat fed varied widely. Diarrhea occured in some animals especially after feeding hydrolysed corn oil.
Details on distribution in tissues:
Absorbed fat is mainly transported via lymphatic channels to the systemic circulation whether fed as glycerides or as fatty acids.

Metabolite characterisation studies

Details on metabolites:
A complete hydrolysis of the fat in the intestinal lumen might occur in the rat.

Any other information on results incl. tables

The proportions of neutral fat and phospholipids in the lymph were in all three cases about the same. 90% of the fatty acids were present in the neutral fat and the remaining 10 % in phospholipids. The neutral fat consisted chiefly of triglycerides; cholesterol and cholesterol esters representing only a minor part of this fraction. No free fatty acids or soaps appeared in the lymph.

The results indicated that glycerides might be completely hydrolysed in the intestinal lumen of the rat and then resynthesized in the intestinal wall.

Applicant's summary and conclusion

Mean absorption rate of corn oil combined with palmitic acid was between 57 - 62 %.