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A MODIFIED RESIDUAL METHOD TO ESTIMATE THE ZERO‐ORDER ABSORPTION RATE CONSTANT IN A ONE‐COMPARTMENT MODEL
Author(s) -
LIU XINGRONG,
BROUWER KIM L. R.,
POLLACK GARY M.
Publication year - 1997
Publication title -
biopharmaceutics and drug disposition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 58
eISSN - 1099-081X
pISSN - 0142-2782
DOI - 10.1002/(sici)1099-081x(199703)18:2<93::aid-bdd2>3.0.co;2-1
Subject(s) - residual , constant (computer programming) , mathematics , chemistry , absorption (acoustics) , nonlinear regression , reaction rate constant , elimination rate constant , statistics , analytical chemistry (journal) , regression analysis , chromatography , kinetics , physics , algorithm , volume of distribution , pharmacokinetics , computer science , medicine , programming language , acoustics , quantum mechanics
The objective of this work was to develop a simple residual method to estimate the rate constant for actual or apparent zero‐order absorption into a one‐compartment model. The method is based on the fact that, in theory, a plot of residuals versus e − Kt is linear for a zero‐order absorption process, where K represents the elimination rate constant governing the terminal phase of the concentration–time profile. The apparent absorption rate constant ( K 0 ) can be calculated from the slope and intercept of the residual plot. Simulated concentration–time data with superimposed random error (CV=5, 10, 15%, n =8), as well as data sets from the literature for hydroflumethiazide and theophylline were analyzed with the proposed method of residuals. Parameters derived with the new technique were compared to both the nonlinear least‐squares regression and the Wagner–Nelson method, all of which yield comparable K 0 estimates. These results indicate that the proposed method of residuals represents a simple approach for estimating the apparent zero‐order absorption rate constant analogous to classic residual analysis for first‐order absorption. ©1997 by John Wiley & Sons, Ltd.