From: Suzette Blanchard <suzette@sdac.harvard.edu> Subject:[NMusers] initial condition model Date: 7/24/2003 8:25 PM Greetings, Could someone help me with how to set up an initial condition - one compartment model with first order absorption (i.e. a recursive one compartment model with first order absorption that would allow a random effect on the initial concentration) in NONMEM? Thank you, Suzette ================================= Suzette Blanchard, Ph.D. Research Scientist Frontier Science Foundation 1244 Boylston St. Suite 303 Chestnut Hill, MA 02467 Email: suzette@sdac.harvard.edu Phone: (617) 632-2007 Fax: (617) 632-2001 _______________________________________________________ From: Lewis B Sheiner <lewis@c255.ucsf.edu> Subject: Re: [NMusers] initial condition model Date: 7/25/2003 2:14 PM Suzette, You seem to want an intial condition on the state vector, in which case the usual trick is to put a unit 'dose' into the central compartment at time zero, associated with a value of F for that compartment (and for time 0 only) which equals a (new) theta plus a (new) eta (see http://www.cognigencorp.com/nonmem/nm/99oct052000.html for an extended discussion). However, in the spirit of the approach & discussion at http://www.cognigencorp.com/nonmem/nm/99apr022003.html, you might instead set F for the 'initializing' dose equal to the observed (individual-specific) baseline concentration value times V, plus a (new) eta whose variance is constrained to equal that of the observation error. LBS. -- _/ _/ _/_/ _/_/_/ _/_/_/ Lewis B Sheiner,MD (lbs@c255.ucsf.edu) _/ _/ _/ _/ _/ Professor: Lab. Med., Biophmct. Sci. _/ _/ _/ _/_/_/ _/_/ Mail: Box 0626, UCSF, SF,CA,94143 _/ _/ _/ _/ _/ Courier: Rm C255,521 Parnassus,SF,CA,94122 _/_/ _/_/ _/_/_/ _/ 415-476-1965 (v), 415-476-2796 (fax) _______________________________________________________