Pharmacokinetic Models | One Compartment Open Model IV Bolus | Unit 3 Biopharmaceutics 6th Sem

This educational video is part of Unit 3 in 6th semester Biopharmaceutics, focusing on pharmacokinetic models. The instructor begins by explaining that pharmacokinetic models are hypothetical tools used to understand drug ADME (Absorption, Distribution, Metabolism, Excretion) in the body. He introduces three main approaches: compartment models, non-compartment models, and physiological models, with primary focus on compartment models. The lecture extensively covers mamillary models where the blood acts as a central compartment connected to peripheral compartments representing body tissues. The instructor explains the notation system for rate constants (K) between compartments and demonstrates how drug movement is represented using arrows and mathematical expressions. The main focus shifts to the one compartment open model for IV bolus injection, which is identified as the most important exam topic. In this model, the entire body is considered as a single uniform compartment with instantaneous drug distribution. The mathematical derivation shows how to calculate elimination rate constant (ke), elimination half-life (t1/2 = 0.693/ke), and clearance from plasma concentration versus time data. The instructor emphasizes that this is the most frequently asked long-answer question in exams and provides the mathematical framework including differential equations and their integration to derive the final logarithmic relationship used for parameter calculation.