Chinese Journal of Physiology

84 : C. PAK anp B, E. READ

IT. The minimum lethal dose.

1. Dogs.—Using the hydrochloride salts we repeated the work of Chen (4) upon ephedrine sulphate and made further tests of the lethal dose of ephetonin and pseudoephedrine. The results in table 1 confirm Chen’s figure (4) for ephedrine and show that ephetonin is only 70 per cent as toxic and pseudoephedrine is 54 per cent.

TABLE 2,

The M.L.D. of ephedrine, ephetonin and pseudoephedrine in white rabbits by intravenous injection of 5 per cent solutions

Sa a Se a Ephedrine HC] | Ephetonin HCI | _Psendoephedrine HC1 Dose | Rabbits} Rabbits || Dose |Rabbits Rabbits | Dose _ | Rabbits) Rabbits perkg | used died || perkg | used died || perkg | used died | | mg mg | mg | 40 2 0 58 1 0 65-S0 5 0 50 2 2 60 3 1 || 100-11 10 3 60 1 1 70 3 2 | 120 3 1 130 4 3 80 3 2 } 185 3 3 70 1 1 | 140 | 2, 2 Ot July 1928. Temperature 29° to 30°C. 2. Rabbits. —The M.L.D. in white rabbits by intravenous injection

did not show identical results for ephedrine and ephetonin as reported by Chen (3). Pseudoephedrine is least toxic to the white rabbit, and by this path of administration shows a greater difference from ephedrine than by any other (see table 2). On the other hand for gray rabbits (see table 3) pseudoephedrine is highly toxic while ephetonin is more toxic to. white rabbits than to gray rabbits by intravenous injection (see table 4). Subcutaneously in the gray rabbit the relative effects of the three isomers is similar to intravenous injection in the dog (see. table 4). In all cases both in dogs and rabbits ephedrine, ephetonin and pseudoephedrine show different degrees of strength similar in proportion to our results from these animals in blood pressure experiments previously reported.

3. White rats.—Excluding our results with the hamster which are discussed separately, ephedrine and ephetonin showed the closest similarity of results of any, by subcutaneous injection in the white rat, see table 5. Chen (4) found the M.L.D: in the rat by intravenous injection quite large, nearly twice as great as in other animals like the dog and