Fd Cosmet. Toxicol. Vol. 7, pp. 279-281. Pergamon Press 1969. Printed in Great Britain

SUMMARY OF TOXICOLOGICAL DATA

FEEDING STUDIES ON LAURIC DIETHANOLAMIDE IN RATS AND DOGS

(Summary* of an unpublished report (dated 19 May 1965) by the Food and Drug Research Laboratories Inc., Maspeth 78, New York 11378, USA, and commissioned by The Monsanto

Co., Springfield, Massachusetts, USA)

Introduction

Laurie diethanolamide (N,N-bis(hydroxyethyl)dodecanamide; LDE) finds use as an anti- static agent in plastics, including some used for food packaging. On the evidence obtained in the present report, a petition was filed with the Food and Drug Administration on 11 August 1965 seeking clearance for the use of LDE as an antistatic agent in polyethylene containers for any foodstuffs except milk and baby food. The petition was subsequently modified and, as a result, Section 121.2527 (Antistatic and/or Antifogging Agents in Food- packaging Materials) was amended on 27 February 1969 to provide for the use of LDE in moulded or extruded polyethylene containers for contact with honey, chocolate syrup, liquid sweeteners, condiments, flavour extracts and liquid flavour concentrates, grated cheese, cream, yoghurt, and dry solids with surfaces containing no free fat or oil. The LDE may be used only at levels not exceeding 0.5 % (w/w) of the container. It must be produced by the reaction of diethanolamine with methyl laurate and must have a minimum melting point of 36°C and a minimum amide content of 90 ~o and contain at most 2 ~ (w/w) free diethanolamine and 0.5 ~o (w/w) N,N'-bis(2-hydroxyethyl)piperazine.

The sample of LDE used in the short-term feeding studies in rats and dogs conformed to the US Toilet Goods Association Standard issued on 27 June 1960.

Short-term feeding study in rats

Experimental design and conduct. Groups of 20 male and 20 female weanling rats of the Food and Drug Research Laboratories' Wistar-derived strain received Purina Laboratory Chow diets providing 0, 25, 80 or 250 mg LDE/kg body weight/day for 13 wk. On this regime, rats received dietary concentrations progressively increasing from 210 to 500, 670 to 1600 and 2100 to 5000 ppm for the lowest, intermediate and highest dosed test groups respectively. Body weights of all rats and food consumption of ten rats/sex/group were recorded weekly. Haematological and clinical-chemistry studies were carried out at 6 and 12 wk in 50% of the animals in each group. Autopsy was performed after 13 wk on test. Organ weights were recorded and gross pathological examination was carried out for all groups, but histological examination was confined to the control and 250 mg/kg/day groups.

General health. LDE had no effect on the behaviour, appearance or condition of the rats.

*Prepared by BIBRA and published with the permission of the companies concerned. 279

280 SUMMARY OF TOXICOLOGICAL DATA

Body weight and food consumption. Rats on 25, 80 or 250 mg LDE/kg/day grew and ate as well as the control group. Efficiency of food utilization was not affected by the test diets.

Haematology. None of the test levels of LDE exerted a significant effect on haemoglobin concentration, haematocrit, total or differential leucocyte counts or prothrombin time either at 6 or 12 wk.

Clinical chemistry. No differences were seen between control and test groups in respect of blood urea, serum levels of glutamic-oxalacetic transaminase and lactic dehydrogenase, or urine findings (specific gravity, pH, albumin, glucose and microscopic sediment) at either 6 or 12 wk. An increase in blood glucose in the group on the 250 mg/kg diet was statistically significant only in the males and had returned to normal by wk 12. In view of its transience, this effect was considered incidental.

Mortality. No deaths occurred in the control or test groups. Organ weights. Slight increases seen in the ratios of liver and kidney weights to body

weight in females receiving 80 or 250 mg/kg/day were not statistically significant. The relative liver and kidney weights in the remaining test groups and the relative weights of the spleen, heart, caecum, gonads, thyroids, pituitary and adrenals in all test groups fell within the control range.

Gross pathology. No significant changes between the control and test groups were seen in the gross appearance of a wide range of organs.

Histopathology. Histological changes in both sexes of the 250-mg/kg group were com- parable with the spontaneous lesions found in the control group. Histological examinations were not carried out on the 25- and 80-mg/kg groups.

Short-term feeding study in dogs Experimental design and conduct. Groups of four male and four female pure-bred beagles

(5-7 months old) were fed New Purina Dog Meal containing 0, 500, 1600 or 5000 ppm LDE, 6 days/wk for 12 wk. Food intake was recorded daily and body weight bi-weekly. After 6 and 12 wk on test, haematological and clinical-chemistry studies were carried out. Terminally, the major organs were weighed and gross and histological examinations were conducted on a wide range of organs from the control and all test groups.

General health. LDE had no effect on the behaviour, appearance or condition of the dogs. Body weight and food consumption. There were no significant differences in growth rate

between control and test groups, but the largest weight gains were recorded in rats on LDE. Food intake and efficiency of food utilization were comparable in the control and test groups.

Haematology. Haemoglobin concentration, haematocrit, total and differential leucocyte count and prothrombin and coagulation times were comparable in control and test groups at both 6 and 12 wk.

Clinical chemistry. Blood levels of glucose and urea, serum levels of glutamic-oxalacetic transaminase and lactic dehydrogenase, and the urinary findings (specific gravity, pH, albumin, glucose, acetone, occult blood and microscopic sediment) were similar in control and test groups at 6 and 12 wk.

Mortality. No deaths were recorded in any of the groups. Organ weights. Relative weights of liver, kidneys, spleen, heart, gonads, adrenals,

thyroids and pituitary were comparable in control and test groups. Gross pathology. A low-grade pulmonary infection and other scattered lesions were

randomly distributed between control and test groups.

SUMMARY OF TOXICOLOGICAL DATA 281

Histology. Pulmonary damage was evident in all groups but no histological changes could be attributed to LDE treatment.

Summary and Conclusions

The feeding of diets containing up to 5000 ppm LDE to rats or dogs for 13 or 12 wk respectively had no untoward effects on general health, growth, food consumption, haema- tology, clinical-chemistry parameters, survival, relative weights of the major organs or the gross and histological appearance of a wide range of organs. The study has thus established no-effect levels of 5000 ppm in the diet of rats and dogs for a period of approximately 3 months. In rats, dietary concentrations of LDE were adjusted as the study progressed to provide a constant dose based on a mg/kg body weight/day basis, the top dietary level being equivalent to 250 mg/kg/day, whereas in dogs the dietary concentrations were kept constant throughout the study.

[Editor's Note: The outcome of this study in rats and dogs may be compared with other published studies on LDE and on Alromine RU 100 (a condensation product of diethanol- amine and myristic, palmitic and stearic acids) in rats. Gaunt et al. (Fd Cosmet. Toxicol. 1967, 5, 497) estimated the 90-day no-effect level of LDE in the diet of rats to be 1000 ppm. A similar no-effect level was obtained with Alromine RU 100 in a 90-day study in rats carried out by Hunter & Stevenson (ibid 1967, 5, 491).]