4 parameter logistic curve graphpad prism

Journal of Pharmacological and Toxicological MethodsĬomputational tools for fitting the Hill equation to dose-response curves Contents lists available at ScienceDirect Furthermore, HEPB also has the option to simulate 500 response values based on the range of values of the dose variable in the original data and the fit of the Hill equation to that data.

Both programs are found to yield estimated values that are essentially the same as those from standard software such as GraphPad Prism and the R-based nls. HEPB, in addition to providing the above results, also computes the prediction band for the data at a user-defined level of confidence, and determines objective cut-off values to distinguish among response types (sensitive, normal and resistant). The Excel template provides a means to estimate the parameters of the Hill equation and plot the regression line in a familiar Microsoft Office environment. In addition, HEPB draws the prediction band at a user-defined confidence level, and determines the ECĥ0 value for each of the limits of this band to give boundary values that help objectively delineate sensitive, normal and resistant responses to the drug being tested.īoth programs were tested by analyzing twelve datasets that varied widely in data values, sample size and slope, and were found to yield estimates of the Hill equation parameters that were essentially identical to those provided by commercial software such as GraphPad Prism and nls, the statistical package in the programming language R. Here we present two user-friendly and freely available computer programs to fit the Hill equation - a Solver-based Microsoft Excel template and a stand-alone GUI-based “point and click” program, called HEPB.īoth computer programs use the iterative method to estimate two of the Hill equation parameters (ECĥ0 and the Hill slope), while constraining the values of the other two parameters (the minimum and maximum asymptotes of the response variable) to fit the Hill equation to the data. However, estimation of the Hill equation parameters requires access to commercial software or the ability to write computer code. Many biological response curves commonly assume a sigmoidal shape that can be approximated well by means of the 4-parameter nonlinear logistic equation, also called the Hill equation.

Abstract of research paper on Computer and information sciences, author of scientific article - Sudhindra R.

4 parameter logistic curve graphpad prism