Hello everyone, I have encountered a problem using the Phoenix Modeling and WNL5 Classical Model PK Model simulation tool. I have obtained a 2-cp Phoenix Model which can describe my data fairly accurately (see the ln DV, IPRED vs TAD file attached). When I try to reproduce this model in WNL5 Classical Modeling PK model, using the simulation feature with the parameters obtained from the Phoenix Model and the same dosage, I get a five-fold decrease in the concentration estimation (see the Predicted Y vs X plot). This is the first time this has gone wrong and I am very surprised. The reason why I switch between Phoenix Model and WNL5 Classical Modeling is simply because of the ease of simulation in the latter. Does anyone have an explanation to this phenomenon? Any help/comment would be appreciated as I am quite new to Phoenix WNL. Best regards, ykl [file name=Ind_DV_IPRED_vs_TAD.bmp size=3145782]Certara | Drug Development Solutions [file name=Predicted_Y_vs_X.bmp size=3145782]Certara | Drug Development Solutions (3 MB)Ind_DV_IPRED_vs_TAD.bmp (3 MB)
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Hello, Would you be able to attach your Phoenix project? I don’t have any ideas from the screenshots. Linda
Yassine, I second Linda’s comment; the project will make it much easier to see what has happened. Most likely there is an error in the dosing in some way. Also with the project we can show you how to convert the phoenix model to simulation mode, its really not too tricky. Simon
Hi again, I am experiencing issues with the server which hosts my installation of Phoenix (just my luck). As soon as it’s up and running I will upload the project file. Thanks for the quick replies.
Hi, Here is the project file. I have solved the issue concerning the low and yes as you suggested something was wrong with the dosing: I had the dosing for multiple subjects included and thought it was enough to map the subjects to “None” in the dosing tab since I was using the mean concentration to model - Phoenix simply summed up the doses of each subject in the column and modeled based on that. I would still like to know how to simulate in Phoenix, especially how to simulate a concentration profile following multiple dosing. Best regards, ykl [file name=Project_group_1_modeling.phxproj size=1809062]Certara | Drug Development Solutions (1.73 MB)
Dear ykl I took your project and added 1 model for simulation and the plot to show you the results. You just need to create a template data set where you define the times and doses you want to use and in run options you select simulation with C as the variable to simulate. This is a simple example and there are other ways to expedite the simulation like the use of ADDL and II. Let me know if you want such examples too. If you want also examples of population simulations , let me know. best Regards; Serge [file name=Project_group_1_modeling-20130623.phxproj size=2202070]Certara | Drug Development Solutions (2.1 MB)
Thank you very much Serge, I got it to work. I would appreciate it if you could show me the Pop PK simulation as well. Best, ykl