The pharmacological assay of digitalis by different methods / by J.W. Trevan [and others].

  • Trevan, J. W. (John William)
Date:
[1928?]
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Licence: In copyright

Credit: The pharmacological assay of digitalis by different methods / by J.W. Trevan [and others]. Source: Wellcome Collection.

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    so calculated is about 5 per cent., so that the difference between the observed figures for the means of the different batches is significant. The ratio of the three batches can also be estimated without reference to any standard curve by the method first used by Krogh for insulin, in which the mortality is plotted against the logarithm of the dose, and parallel straight lines are drawn through the three sets of points obtained. The horizontal differences between the three lines then give the obtained are given by the points @ -- ® for S; V-- ^ for U ; - 4 for D ; x-x for Ouabain. The curves drawn are similar to that in Figure 1, but are altered in shape by the logarithmic scale. logarithm of the ratio of the activities. (See figure 2.) The aorizontal distance between the line drawn for S and U is p'2, the antilogarithm of which is T585, and the distance Detween S and D is O'254, the antilogarithm of which is 1'79, io that the activity of U in terms of S is 158'5 per cent. md D in terms of S is 100 U79 = 55'8 per cent. At present we are using the United States sample of mabain as a routine standard, O'083 mgm. of which should >e equivalent to 1 c.c. of tincture of digitalis of the United Itates Pharmacopoeia. The curve for ouabain taken from lur routine figures during the time of the present experiments ss plotted at T in figure 2. The dotted curves are parallel
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