Modeling of different formulations

From: "Dennis Fisher" fisher@PLessThan.com Subject: [NMusers] Modeling of different formulations Date: Tue, March 15, 2005 8:22 am Colleagues, I am dealing with the following situation: Cohort 1: xx mg of Formulation 1 Cohort 2: xx mg of Formulation 2 Cohort 3: xx/2 mg of Formulation 1 + xx/2 mg of Formulation 2, administered simultaneously. Assume for the moment that the two formulations have different values for ka and F. If I indicate in the data records which formulation is being given (i.e., I need two separate dose records for cohort 3, one for each formulation), F will be handled appropriately (i.e., F acts at the time of dosing so it will apply to the dose). However, I believe that ka will not be handled correctly for cohort 3 - whichever dose record appears second will dictate the ka that is applied. I could work around this by setting up two entirely separate absorption compartments, one for each of the formulations. Does anyone have a clever approach that solves this more simply? Dennis Dennis Fisher MD P < (The "P Less Than" Company) Phone: 1-866-PLessThan (1-866-753-7784) Fax: 1-415-564-2220 www.PLessThan.com