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    FAO Nutrition Meetings
    Report Series No. 40A,B,C
    WHO/Food Add./67.29




    TOXICOLOGICAL EVALUATION OF SOME
    ANTIMICROBIALS, ANTIOXIDANTS, EMULSIFIERS,
    STABILIZERS, FLOUR-TREATMENT AGENTS, ACIDS AND BASES





    The content of this document is the result of the deliberations of the
    Joint FAO/WHO Expert Committee on Food Additives which met at Rome,
    13-20 December, 19651 Geneva, 11-18 October, 19662




                   

    1 Ninth Report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series, 1966 No. 40; 
    Wld Hlth Org. techn. Rep. Ser., 1966, 339

    2 Tenth Report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series, 1967, in press; 


    Food and Agriculture Organization of the United Nations
    World Health Organization
    1967


    BUTYL p-HYDROXYBENZOATE

    Synonym                       Butylparaben

    Chemical names                n-butyl-p,hydroxybenzoate; butyl ester
                                  of p-hydroxy benzoic acid

    Empirical formula             C11H14O3

    Structural formula

    MOLECULAR STRUCTURE 4

    Molecular weight              194.23

    Definition                    Butyl p-hydroxybenzoate contains not
                                  less than 99.0 per cent. C11H14O3.

    Description                   Butyl p-hydroxybenzoate occurs as
                                  colourless micro-crystals or as a white
                                  crystalline powder and may have a slight
                                  odour.

    Use                           As an antimicrobial agent.

    Biological Data

    Biochemical aspects

         Dogs given 1000 mg/kg body-weight of the butyl ester excreted
    only 48.2 per cent. of the dose in the urine within 48 hours.
    Metabolic pathways other than hydrolysis and subsequent conjugation
    may account for the poor recovery of butyl ester metabolites in
    balance experiments (Jones et al., 1956). Dogs fed 1000 mg/kg
    body-weight of butyl ester or given 50 mg/kg body-weight i.v. excreted
    40.48 per cent. of the ester in the urine as metabolites and 0.5 per
    cent. as unchanged ester (Sokol, 1952).

    Acute toxicity

                                                                       

    Animal  Route              LD50,          References
                               mg/kg 
                               body-weight
                                                                       

    Mouse   oral(free acid)    5 000          Sokol, 1952
            oral (Na salt)     950            Matthews et al., 1956
            i.p. (free acid)   230 appr.      Sokol, 1952
            i.p.(Na salt)      230  24       Matthews et al., 1956
                                                                       

    Short-term studies

         Rat. Groups of 12 male and 12 female weanling rats were fed
    dietary levels of 0, 2 and 8 per cent. of butyl ester for 12 weeks. At
    the 8 per cent. level, no males survived the experimental period, the
    mortality rate in the females was higher, than that of the controls,
    and the rate of weight gain was markedly affected; the animals at this
    level also showed depression and decreased motor activity. However,
    autopsies with histological examination of animals dying during the
    test showed only pneumonia and pulmonary consolidation, without
    difference between treated and control animals. Food consumption was
    unaffected in all groups and necropsy of all survivors showed no
    difference other than the body-weight depression at 8 per cent.
    (Matthews et al., 1956).

    Long-term studies

    None available.

    Comment on experimental studies reported

    No adequate studies on this substance are available. A toxicological
    evaluation is impossible.

    REFERENCES

    Jones, P. S., Thigpen, D., Morrison, J. L. & Richardson, A. P. (1956)
    J. Amer. Pharm. Ass., sci. Ed., 45, 260

    Matthews, C., Davidson. J., Bauer, E., Morrison, J. L. & Richardson,
    A. P. (1956) J. Amer. pharm.  Ass., sci, Ed.,  45, 260

    Sokol, H. (1952) Drug Stand., 20, 89
    


    See Also:
       Toxicological Abbreviations