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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


    SODIUM CARBOXYMETHYLCELLULOSE

    Synonyms                     Sodium cellulose glycolate; Na-CMC; CMC

    Chemical name                Sodium salt of a carboxymethyl ether of
                                 cellulose.

    Chemical formula

              [C6H7O2(OH) x (OCH2COONa)y]n

              where x = 2.00-2.40
                    y = 1.00-0.60
                    x + y = 3.00

    Structural formula

    MOLECULAR STRUCTURE 17

    Molecular weight             Unsubstituted structural unit: 162.14

                                 Monosubstituted structural unit:  242.16

                                 Macromolecules:  from about 21 000 
                                                  (n about 100)

                                 up to 500 000 (n about 2000)

    Definition                   Sodium carboxymethylcellulose is the
                                 sodium salt of a carboxymethyl ether of
                                 cellulose, where the substitution degree
                                 ranges from 0.20 to 1.00. After drying
                                 at 110 to constant weight it contains
                                 not less than 99.5 per cent. of sodium
                                 carboxymethylcellulose.

    Description                  Sodium carboxymethylcellulose is a white
                                 or a slightly yellowish, almost
                                 odourless and tasteless hygroscopic
                                 powder, consisting of very fine
                                 particles, fine granules, or fine
                                 fibres.

    Uses                         Thickener, binder, emulsifier,
                                 stabilizer and colloidal suspending
                                 agent in salad dressing, fruit pie
                                 fillings, baked goods, dietetic foods
                                 and many others.

    Biological Data

         This additive was evaluated by the Joint FAO/WHO Expert Committee
    on Food Additives in its Seventh Report (FAO/WHO, 1964). Since its
    publication some new experimental work has been carried out on these
    compounds. This and other work not included in the Seventh Report is
    presented and discussed in this monograph.

    Long-term studies

         Mouse. Groups of 50 male and 50 female mice were maintained for
    up to 100 weeks on ad lib. diets containing 0, 0.1 and 1 per cent.
    of sodium carboxymethylcellulose. There was no apparent difference in
    mortality and tumour incidence between the groups (Imperial Chemical
    Industries, 1966).

         Rat. Groups of 50 male and 50 female rats were maintained for
    up to 2 years on ad lib. diets, containing 0, 0.1 and 1 per cent. of
    sodium carboxymethylcellulose. No difference in mortality and tumour
    incidence was apparent between the groups (Imperial Chemical
    Industries, 1966).

    Comments

         The additional information supports the previous evaluation of
    sodium carboxymethylcellulose.

    Evaluation

    Level causing no toxicological effect

         Mouse. 10 000 ppm in the diet, equivalent to 1500 mg/kg
    body-weight/day

         Rat. 10 000 ppm in the diet, equivalent to 500 mg/kg
    body-weight/day

    Estimate of acceptable daily intake for man

                                     mg/kg body-weight

        Unconditional acceptance          0-301

        Conditional acceptance:      Higher levels may be used for
                                     dietetic or calorie control purposes

    REFERENCE

    Imperial Chemical Industries (1966) Unpublished reports submitted to
    WHO.


                   

    1 As sum of total cellulose derivatives
    


    See Also:
       Toxicological Abbreviations