What Is the Two-Compartment Pharmacokinetic Drug Infusion Calculator?
The two-compartment pharmacokinetic model represents drug distribution between blood (central) and peripheral tissue reservoirs.
How Does the Two-Compartment Pharmacokinetic Drug Infusion Calculator Work?
Micro-rate constants (k10, k12, k21) define an algebraic quadratic characteristic equation whose roots yield distribution rate alpha and elimination rate beta.
Two-Compartment Pharmacokinetic Drug Infusion Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
C_{ss} = rac{k_0}{ ext{CL}}, quad r^2 + (k_{10} + k_{12} + k_{21}) r + k_{10} k_{21} = 0, quad t_{1/2,eta} = rac{ln(2)}{eta}
Two-compartment open model characteristic roots and steady-state concentration equations.
How to Use the Two-Compartment Pharmacokinetic Drug Infusion Calculator
- Enter constant infusion rate in mg/hr, systemic clearance in L/hr, central volume Vc, peripheral volume Vp, and distribution clearance Q.
Step-by-Step Example Calculation
Intravenous Anesthetic Infusion (e.g., Propofol)
Input Values:
infusionRateMgHr:60
clearanceLHr:12
centralVolumeVc:25
peripheralVolumeVp:50
intercompartmentalClQ:18
Worked Steps: Steady-state Css = 5.00 mg/L, Distribution t_1/2,alpha = 0.45 hr, Elimination t_1/2,beta = 3.82 hr.
Understanding Your Result
Displays steady-state plasma concentration Css, rapid alpha distribution half-life, and terminal beta elimination half-life.
Factors That Affect the Result
- High tissue binding expands peripheral volume Vp, prolonging terminal elimination half-life.
When Should You Use This Calculator?
- Target-controlled infusion (TCI) anesthesia, therapeutic drug monitoring of antibiotics (vancomycin, aminoglycosides), and chemotherapy regimen design.
Assumptions & Limitations
- Assumes first-order linear elimination and distribution kinetics without metabolic enzyme saturation.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard classical two-compartment pharmacokinetic formulation.