Chinese Journal of Physiology

COMPARATIVE TOXICITY OF EPHEDRINES 83

injection, and Chen (4) brought the figures within the narrower limits of 320 to 400 mg. He also administered the drug orally and intraperitoneally. We have only repeated the series by intravenous injection which for the sulphate Chen gave as high a figure as 66 to 70 mg.

EXPERIMENTAL I, Administration of the drugs.

These experiments have extended over two years, during which time season and temperature have shown a marked influence upon the results obtained. This was especially so in the case of the hamster, which may show 100 per cent difference in the minimum lethal dose in midsummer and autumn, The doses of ephedrine definitely fatal when summer heat was between 35° and 38°C, were well tolerated in early autumn when the temperature dropped to 24° to 27°. The usual technique was followed for subcutaneous, intravenous and intraperitoneal injection, care being taken to use solutions of the isomers of similar concentration, for we observe differences in our results when the strengths of the solutions have too great a variation.

In frogs the drug was injected through the mouth into the anterior lymph sac. At first it was found difficult to obtain consistent results. Using male frogs only and squeezing out the urine from the bladder, we were able to obtain the desired consistency.

TABLE 1,

The M.L.D. of ephedrine, ephetonin and pseudoephedrine in dogs by intravenous injection of 10 per cent solutions

Ephedrine HCl Ephetonin HCl Pseudoephedrine HCl

> 2 >

» Bly | @ 2 lg » 2 | s

Og A, gd Ay gt Ay

z aw | @ | Results B Aw | BP) Results a Bie) ao BP | Results

mp O° > | ° Pa ys °

3 8/8 3 6 |A 3 8 |A

Pas oy (oe

mg mg mg

7.05kg,9| 50 |Recovered| 3.88kg, %| 90 |Recovered|5.55 kg, $| 100 |Recovered 84 kg, 3} 60 |Dead 5.88 kg, 2| 90 |Recovered|6.95 kg, 9| 100 |Recovered

8.1 kg, 2| 60 |Recovered| 5.59kg, | 99 |Dead 415kg, 9) 110 |Recovered 4.6 kg, 2| 60 |Recovered| 4.00kg, 3 100 |Recovered|6.91kg, $| 110 |Dead

7.75 kg, 2) 70 |Dead 9.43 kg, 2) 100 |Dead 3.67 kg, 3| 120 |Recovered

5.7 kg, 2| 70 |Dead 13.77 kg, 3| 100 |Dead 9.34 kg, &| 120 |Recovered 5,05 kg, 2} 110 |Dead 7,55 kg, 2| 120 |Dead 5.78 kg, | 110 |Dead 5.53 kg, 9| 180 |Recovered

3.56kg, 9} 1380 |Dead 6.96 kg, $| 180 |Dead

July 1928. Temperature 29°to 32°C.