A very nice tutorial from P Dua, E Hawkins and PH van der Graaf appeared last year in CPT:PSP around TMDD based models, with an introductory guide to the mathematical aspects of TMDD models for pharmaceutical researchers.
http://onlinelibrary.wiley.com.proxy1.athensams.net/doi/10.1002/psp4.41/abstract
Marc Lavielle (@lavielle) has implemented the 8 models described in this tutorial (and for which a BM code is provided as Supplementary Material), using the mlxR package and Shiny applications:
http://simulx.webpopix.org/case-studies/tmdd/
It is possible with these web applications to interactively modify the parameter values and the dosing regimen, and visualize the impact on the different components of the ODE system.
All the R code and the Shiny applications are also available:
http://simulx.webpopix.org/simulx/tmddmlx.zip
@lavielle, much thanks!