Noncompartmental Pharmacokinetics Analysis — PO + IV Bolus (single-dose)
Study Design

PO（Extravascular）

IV (Bolus)

AUC 使用 Linear Trapezoidal with Linear Interpolation；PO 在给药时刻缺失时补 C=0，IV Bolus 在给药时刻缺失时按初始两点规则回推 C0。λz 使用终末相 log-linear 回归并按 adjusted R² 选择最佳区段。
PO Concentration Data
Excel multi-cell paste is supported. Select the first cell and paste rows × columns directly. Input cells are blank by default.
IV (Bolus) Concentration Data
Excel multi-cell paste is supported. Select the first cell and paste rows × columns directly. Input cells are blank by default.
PO Pharmacokinetic Parameters
CL/F、Vz/F 为表观参数；MRT 为 MRTINF(obs)。
IV (Bolus) Pharmacokinetic Parameters
IV 参数包括 CL、Vz、Vss、C0（终末相回推，仅作参考）。
PO vs IV Derived Parameters
Concentration–Time Profile
Calculation Methods
NCA models
[Phoenix WinNonlin NCA Aligned] PO: Extravascular single-dose (Model 200-equivalent). IV: IV Bolus single-dose (Model 201-equivalent). PO and IV routes are analyzed independently; paired derived parameters are shown only when both routes contain calculable data.
Observed parameters
Cmax and Tmax are taken directly from observed concentrations. Clast and Tlast are the last positive quantifiable concentration and its sampling time used for extrapolation.
AUC / AUMC integration
Linear trapezoidal integration with linear interpolation is used. For PO, if the first observation occurs after dose time, a dose-time point (t=0, C=0) is inserted. For IV bolus, an estimated C0 at t=0 is inserted when needed. AUClast integrates through Tlast.
Terminal λz
ln(C) is regressed versus time using at least 3 positive terminal concentrations. Candidate terminal segments are compared by adjusted R²; when fits are effectively equivalent, the segment with more points is preferred. For PO, automatic terminal selection does not start before Cmax.
Extrapolation
AUCINF_obs = AUClast + Clast/λz. AUC_%Extrap_obs = 100 × (Clast/λz) / AUCINF_obs. AUMCINF_obs adds the standard terminal first-moment extrapolation Clast × (Tlast/λz + 1/λz²).
IV bolus C0
When there is no t=0 sample, C0 is back-extrapolated from the initial log-linear decline using the first two usable positive concentrations; if a valid declining log-linear estimate cannot be obtained, the first observed concentration is used as the fallback.
Secondary parameters
MRTINF_obs = AUMCINF_obs/AUCINF_obs. Clearance is dose/AUCINF_obs after unit conversion. Vz = CL/λz (using clearance in the input time unit). IV Vss = CL × MRTINF_obs. PO CL/F and Vz/F are apparent parameters.
PO vs IV derived parameters
Absolute bioavailability F = 100 × (AUCINF,PO/DosePO)/(AUCINF,IV/DoseIV). MAT = MRTINF,PO − MRTINF,IV. These outputs remain unavailable when either route cannot be calculated.
Units and missing values
Blank cells are treated as missing, not zero. Clearance is reported as mL/min/kg and volume as mL/kg for mass-concentration inputs. Molecular weight is required for molar/mass concentration conversion.
Scope
This page implements the current WinNonlin-aligned settings shown here. Other Phoenix choices—different trapezoidal methods, manual λz ranges, BLQ policies, exclusions, partial AUCs, infusion or multiple-dose models—can produce different results.
Acknowledgement / Third-Party Notices

UI attribution. Portions of this application's user-interface layout were inspired in part by the open-source Plotly Dash sample application Pharmacokinetics Calculator (dash-pk-calc). The original Dash sample application is distributed under the MIT License. Original project: Plotly dash-sample-apps / dash-pk-calc.Independent implementation and extensions. The PK/NCA calculation engine in this application is implemented separately and has been substantially extended, including separate PO and IV bolus handling, additional pharmacokinetic parameters, unit conversions, terminal-phase estimation, PO-vs-IV calculations, and absolute bioavailability (F%). These functions should not be interpreted as functions supplied by, or representations made by, the original Dash sample application.Phoenix / WinNonlin notice. Phoenix and WinNonlin are products/trademarks of Certara. This application is not affiliated with, sponsored by, endorsed by, validated by, or certified by Certara. References such as “Phoenix WinNonlin NCA Aligned” describe the calculation terminology and intended numerical alignment of this independent implementation only; they do not imply official equivalence, regulatory validation, or suitability for any particular regulated use.Use and verification. Pharmacokinetic results produced by this tool should be independently verified when used for research decisions, formal reporting, submissions, or regulated work.

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