Applications of Pharmacokinetics

Rational & Optimal therapy Right Balance between Therapeutic & Tox Applications of Pharmacokinetics Right DRUG Rational & Optimal therapy Right Balance between Therapeutic & Tox

Applications of Pharmacokinetics Ratio Right Balance between Therapeutic & Tox effects Drug Concentration at Site Drug Concentration in Plasma

Applications of Pharmacokinetics Ratio Applications of Pharmacokinetics Max effective conc This is where we want to maintain drug concentration for optimal benefit Therapeutic Window Drug Conc Minimum effective conc Time

Applications of Pharmacokinetics Ratio So for optimal dosing, we need to know mechanism of ADME as well as “KINETICS” of ADME Max effective conc This is where we want to maintain drug concentration for optimal benefit Therapeutic Window Drug Conc Minimum effective conc Time

Key Pharmacokinetic Parameters Ratio Cmax Maximum drug conc, peak plasma conc Cmax depends on Dose Rate of absorption Rate of elimination At Cmax; Rate of absorption = Rate of elimination Ideally, Min effect conc < Cmax < Max effective conc Drug Conc Time

Key Pharmacokinetic Parameters Ratio Tmax Time to reach peak plasma conc Reflects rate of absorption Onset time, Onset of action depends on Tmax Drug Conc Tmax Time

Key Pharmacokinetic Parameters Ratio AUC Area Under the curve Represents amount of drug that enters systemic circulation after administration Represents extent of absorption Important parameter to estimate bioavailability Drug Conc Time

Pharmacokinetic Analysis Ratio Pharmacokinetic Analysis Drug absorption, distribution, elimination is complex process We need simple approach to DESCRIBE, ANALYSE & INTERPRET PK data Drug Conc Time

Pharmacokinetic Analysis Ratio Pharmacokinetic Analysis Two major approaches to quantitative study of PK data Model Based approach Model-Independent approach Drug Conc Time

That uses mathematical terms Ratio Model- Based approach What's a PK MODEL ?? It’s a HYPOTHESIS Drug Conc That uses mathematical terms To describe PK data Time Hypothesis is a proposed explanation, in this case of drug ADME process

Ratio Types of PK Models Compartment Model Physiological Model

What are Compartment Model ? Ratio What are Compartment Model ? As the name suggest, body is assumed to be made up of “Compartments” These compartment are connected to each other Within each compartment, the drug get’s rapidly distributed & uniformly distributed (Well stirred model)

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