If we fit a 1 cpt model with first order elimination and first order absorption and volume to single dose plasma concentration time values after a given dose then one obtains the values for the fitted PK paramaters. Use of the fitted paramaters enables us to simulate plasma concentration values following multiple doses at time points.[
Now what I would like to do is the following. I have the following:
(a) the plasma concentration and time values after two doses {precise times known but the precise doses are not known} of the drug.
( the plasma concentrations and the 1 cpt model paramaters i.e. K01, K10 and V fitted paramater after one single dose of the drug (known amount).
I reason that I should be able to simulate the values of the two doses {Aa1 and Aa2} to fit the multiple dose plasma concentrations. The times of administration of Aa1 and Aa1 are known. Can this be done?
The inputs would be the values of the PK paramaters plus the dosing time of each of the two doses.
I think this can be done by a Phoenix model? I do not envisage using lag times to set the timing of the two doses. I enclose a photo plus a file. I need advice on how to do this since I do not understand the Phoenix system model very well. I envisage a worksheet with 0 and 4 hours {times of dose} and Aa1 and Aa2 being mapped to these times?
Also I enclose a file of my efforts. Advice is most appreciated,
Angus [file name=estimate_multiple_doses-20130306.phxproj size=365220]http://pharsight.com/extranet/media/kunena/attachments/legacy/files/estimate_multiple_doses-20130306.phxproj[/file]