Simulation using model 3

Phoenix Certara Forums Phoenix WNL basics
1

Hi Can you please explain what exactly is meant by V_F, K01 and K10. How and from where to get these values? Thanks and regards, Minaxi Vora

2

Hi Minaxi! [quote]Can you please explain what exactly is meant by V_F, K01 and K10.[/quote] See the User’s Guide page 625. V is the volume of distribution. F is the (absolute) bioavailability (range 0-1). The latter is unknown if fitting extravascular data. K01 is the absorption rate constant (unit 1/time) and (transfer to “outside” = “0” to the central compartment “1”). K10 is the elimination rate constant (from !1" to “outside”). [quote]How and from where to get these values?[/quote] From a model fit of your data or from the literature.

3

Hi I am not very clear. Is it possible to perform Steady State Simulation using Model No. 3 for the attached data and explain? I have tried to do the same but not very sure whether I have done it correctly. I have also attached the charts obtd. on performing SS using Model 3, considering 12mg dose given for 12 days. thanks and regards, Minaxi Vora

SS_PK_Chart_391_Test_mean__model_3_12_days_310312.JPG
SS_PK_Chart_391_Test_mean__model_3_12_days_310312.JPG814×411 66.2 KB
SS_PK_Chart_391_Test_mean__model_3_12_days_310312.JPG
SS_PK_Chart_391_Test_mean__model_3_12_days_310312.JPG814×411 66.2 KB

4

Hi Minaxi - as you probably noticed there are a couple of issues with attachments in the forum - I edited your message to display your graph. Looking at your graph it seems you have simulated 12 doses OK, but without knowing what your original single-dose data was like or from what dose it was obtained I can’t say if this is correct. I think you should be clearer in what question you are trying to answer, PK theory suggests steady-state is obtained in 5-7 half-lives, so performing a simulation isn’t ‘proving’ whether SS has been obtained - is there a minimal conc you want ot maintain, or a maximum conc you want to stay below? Are you interested in secondary parameters like Cmax, AUC etc. or in defining what sampling schedule would be good for a proposed sampling design? Simon.

5

Hi Simon, I think the file with initial data to be simulated was not attached properly. I had attached file with time-conc data and the graphs. I am resending the file for your reference. If you can just run it for steady state simulation and explain, I would be highly obliged. Thanks and regards, Minaxi Vora NB: I think .pwo file is not being attached, I have reattached .xls file Sorry for inconvenience [file name=SS_data_020412.xls size=23040]Certara | Drug Development Solutions (22.5 KB)