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DÍEZ MONTORO, R. & COL. AN. R. ACAD. NAC. FARM.

The values of AICc indicate that the Eq. 4 is significantly better
than Eq. 3. The fact that the ecuation Eq. 4 is biexponential indicates
that the process consist of two different chemical reactions. It also
happens with the other studied variables, althoug the comparison is
included only in this case.

Eq. 4 is obtained from Eq. 2 by substitution:

z = ze1+ (z01-ze1)(exp(-t (z01k’1+q? (k’-1-k’1)))) + ze2 + (z02-ze2)(exp(-t

(z02k’2+qe (k’-2-k’2)))) Eq. 2

ze1 = a·m/(m+b) (Langmuir)

z01 = c·m/(m+d) (Langmuir)

z01k’1+qe (k’-1-k’1) = e

ze2 = f·m

z02 = g·m/(m+h) (Langmuir)

z02k’2+qe (k’-2-k’2) = j

Eq. 4 shows that the initially obtained z values are dependent of

m as per Langmuir model (30). The z values at equilibrium are di-

rectly proportional to z0 (empirical observation). The apparent rate
constants are independent from z0, and therefore of m. This is ex-
plained admitting that the used concentrations of tracer are signifi-

cantly inferior to those of Insulin.

5.2. Influence of q (Experiments 4, 5, 6, 7)

The results of experiments 4,5,6,7 are fitted to the equation:

z=(a-b·q)+(c+d·q)·exp(-t·(e+q·f))+(g+h·q)·exp(-t·(j+q·k)) Eq. 5

Its parameters, coefficient of correlation and sum of squares of
residuals are:

a = 2554, b = 32.3, c = 1976, d = 193, e = 5.17, f = -50.5·10-3, g = 7216,
h = -160.7, j = 0.0297, k = -0.669·10-3, r = 0.995, s = 2.84·106

Eq. 5 is obtained from Eq. 2 by substitution:
ze1 + ze2 = a-b·q

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