ISSN:
1432-1041
Keywords:
Nonlinear kinetics
;
Cyclosporin
;
Michaelis-Menten equation
;
1-exp function
;
renal failure
;
hepatotoxicity
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Summary The basic law in nephropharmacology states that pharmacokinetic parameters depend linearly on renal function. Few exceptions to linear dependence have been reported, e.g. substances with saturable tubular reabsorption or secretion. A further example is cyclosporin, which was found to be eliminated according to log-concave nonlinear kinetics in 3 patients with hepatotoxicity after kidney transplantation. The nonlinear cyclosporin kinetics were computer-fitted to the integrated forms of the 1-exp function and the Michaelis-Menten equation by nonlinear regression analysis. The same maximal velocity (Vmax = 23 ng ml−1 h−1) and Michaelis constant (Km = 686 ng ml−1) were calculated for cyclosporin when applying either the 1-exp function or the Michaelis-Menten equation. The nonlinear elimination of cyclosporin, however, was described even more closely by the 1-exp function than by the Michaelis-Menten equation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01428388
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