Hi Jing, Testing covariates on dispostition of your long acting injectable all depends on the pharmaceutics. E.g., if you have an intramuscularly injection of a nano-suspension, you might want to consider a zero order process for the release of the drug in the systemic circulation and see whether particle size impacts dissolution rate. In any case, think about the pharmaceutical plausability first before testing a covariate.
Cheers, Rob Van: owner-nmus...@globomaxnm.com [mailto:owner-nmus...@globomaxnm.com] Namens Jing Niu Verzonden: zondag 25 september 2016 14:41 Aan: nmusers@globomaxnm.com Onderwerp: [NMusers] covariate on transit compartment model parameters Dear NMusers, I am modeling long-acting injectable formulation using transit compartment model parameterized with mtt (mean transit time) and ntr (number of transit compartment). As I would like to model multiple formulations using the same structure model, adding formulation as a categorical covariate on mtt or ntr separately decreased the OFV significantly (by ~100 units). Considering mtt and ntr are correlated parameters, should I add formulation on both mtt and ntr, or adding to either one is sufficient? Any input is greatly appreciated, Jing PS: I am considering the latter one, due to that the simulations with changing Ktr or ntr generated similar profiles (Fig1 c and d, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636497/pdf/psp201314a.pdf). Het Radboudumc staat geregistreerd bij de Kamer van Koophandel in het handelsregister onder nummer 41055629. The Radboud university medical center is listed in the Commercial Register of the Chamber of Commerce under file number 41055629.
