RE: Non-physiological parameters at lowest OBJ

From: William Bachman <bachmanw@globomax.com> Subject: RE: [NMusers] Non-physiological parameters at lowest OBJ Date: 8/6/2003 8:19 AM Justin, I don't recommend using "non-physiological" constraints for PK parameters (e.g. 7 as lower bound for CL). (Unless proven otherwise to be needed in the course of your analysis.) I start by imposing a lower bound of zero for PK parameters and no upper bound. If there are logical upper and lower bounds for a parameter, then I would use those bounds (e.g. 0 < F < 1.0 for bioavailability, etc.) So, that piece weighs in favor of Case 1. What interindividual error models are you using? May want to try additive error on KA and/or ALAG if you haven't already. On the other hand, if you intend to investigate covariates, you might want to pursue that avenue at this point. William J. Bachman, Ph.D. GloboMax LLC 7250 Parkway Drive, Suite 430 Hanover, MD 21076 410-782-2212 bachmanw@globomax.com