Half-emptying time by Maes/Ghoos method

Half-emptying time t50 as determined from the fit of a beta exponential function. In the Maes/Ghoos model, it is defined as the time when the area under curve (AUC) is 50% of the AUC from 0 to infinity.

Maes B D, Ghoos Y F, Rutgeerts P J, Hiele M I, Geypens B and Vantrappen G 1994 Dig. Dis. Sci. 39 S104-6.

Usage

t50_maes_ghoos(cf)

Arguments

cf

named vector of coefficients; only k and beta are required note that k is measured in 1/min (e.g. 0.01/min), usually it is quoted as 1/h (e.g. 0.6/h).

Value

Time in minutes when area under curve is 50% of the AUC to infinity. In the Maes/Ghoos model, this is used as a surrogate for gastric emptying half time t50.

See also

exp_beta, and t50_bluck_coward for an example.

Examples

# Integral from 0 to infinity is 100 at dose 100 mg
integrate(exp_beta, 0, Inf, beta = 1.5, k = 0.01, m = 1, dose = 100)
#> 100 with absolute error < 0.0014
t50_mg = t50_maes_ghoos(c(beta = 1.5, k = 0.01, dose = 100))
t50_mg
#> [1] 99
# Integral to half-emptying time \code{t50_maes_ghoos} is 50 
integrate(exp_beta, 0, t50_mg, beta = 1.5, k = 0.01, m = 1, dose = 100)
#> 50 with absolute error < 0.0042