CMATRIX: software for physiologically based pharmacokinetic modeling using a symbolic matrix representation system.

Physiologically based pharmacokinetic (PBPK) modeling is based on an understanding of the physical and biological factors governing drug distribution. It is a procedure requiring composition of differential equations describing the distribution of drugs among physiologically defined compartments. CMATRIX is a program that facilitates development of PBPK models. In CMATRIX, the model is represented as a matrix of transfer parameters; the program generates a corresponding system of differential equations, and solves them numerically. This system dramatically improves the ease with which PBPK models can be developed, allowing the freedom to construct subcompartments down to the receptor level.