hillEquation {oro.pet}

Estimation of the Half Maximal Inhibitory Concentration

Description

The half maximal inhibitory concentration (IC50) is a measure of the effectiveness of a compound in inhibiting biological or biochemical function. This quantitative measure indicates how much of a particular drug or other substance (inhibitor) is needed to inhibit a given biological process (or component of a process) by half.

See reference(s).

In this version of the function the maximal occupancy (rmax) is estimated automatically. This should be optional.

Usage

hillEquation(
  conc,
  occ,
  guess = c(1, 100),
  control = minpack.lm::nls.lm.control()
)

Arguments

conc

a vector of drug concentrations in plasma (example units are ng/mL).

occ

a vector of PET occupancy values that correspond to the measured drug concentrations in plasma.

guess

a length-two vector of starting values for the nonlinear optimization.

control

is a list of parameters used by nls.lm.control that are set by default, but may be customized by the user.

Value

List with the following elements

• IC50Half maximal inhibitory concentration

• rmaxEstimated maximal occupancy

• IC50SEApproximate standard error for IC50

• rmaxSEApproximate standard erorr for rmax

• hessianHessian matrix from the Levenburg-Marquardt procedure

• infoReturn value from the Levenburg-Marquardt procedure

• devianceDeviance from the Levenburg-Marquardt procedure

• messageText message from the Levenburg-Marquardt procedure

Author(s)

Brandon Whitcher [e-mail]

References

Hill Equation IC50

See Also

nls.lm