Hello everyone, I have performed intraperitoneal (IP) and subcutaneous (SC) pharmacokinetic study in mice. Then I did NCA with Linear Trapezoidal and Linear Interpolation and got AUCINF_OBS =. 758404.86. In addition to this I also performed WNL 5 Classic PK model no. 7 and obtained AUC =293061.38 ( less than half of value obtained in NCA ). Then I changed the Calculation method from Linear Trapezoidal Linear Interpolation to Linear Trapezoidal Linear/Log Interpolation giving the AUCINF_OBS= 249562.2 which is similar to the value obtained by PK model. Based on the above context my queries for IP PK study are: 1. Which one is the correct approach/ which values should I report: NCA or PK model or both of them to confirm that they give similar values? 2. Does the Beta HL of PK model represent the same thing as the HL_lamdaz of NCA? Based on the above context my queries are for SC PK study: I began with WNL 5 Classic PK model 11 (First order input 2 compartment model) to fit the SC data but it not proceed giving the error: Fail to fit the model. Then I tried using Model 7 (IV bolus input with 2 compartment model) and obtained a good fit. My question is: Will it be a correct approach to fit Model 7 to a data for where the route of administration is subcutaneous instead of IV bolus? I am also attaching my Phoenix file. Thanks, Chetan [file name=QA_pharsight.phxproj size=713277]/extranet/media/kunena/attachments/legacy/files/QA_pharsight.phxproj[/file]QA_pharsight.phxproj (697 KB)