The first-order elimination rate constant is the rate constant for the elimination of the drug from the body. The elimination rate constant and the half life are dependent on the total body clearance and the volume of distribution of the drug.

This rate constant represents drug elimination through all routes of drug elimination such as metabolism, renal excretion, and other routes.

The first-order elimination rate constant has units of time^-1.

The semilog graph paper allows plotting the data at logarithmic intervals without doing the actual logarithmic transformation of the numbers.

In order to determine the slope of a line drawn on a semilog graph paper it is necessary to do logarithmic transformation for the y values. The slope of the line in this case will be determined from the following relationship:

A semilog graph paper is a graph paper in which the x-axis is a normal linear scale, but the y-axis is a logarithmic scale. Semilog graph paper allows plotting the data at logarithmic intervals without the need for logarithmic transformation.

The y-axis is divided into cycles, each represents 10-fold increase in values (a single log₁₀ unit).

The total body clearance is the volume of the plasma or blood which is completely cleared from the drug per unit time. It has units of volume/time.

The CL_T for a drug is constant within a patient (dose and concentration independent) when the elimination processes follow first-order kinetics.

The total body clearance is a measure of the efficiency of all eliminating organs in eliminating the drug and it is the sum of all organ clearances (i.e. CL_T is the sum of the renal clearance, hepatic clearance and all other organ clearances).

The elimination rate constant and the half life (the dependent pharmacokinetic parameters) are dependent on (is determined from) the total body clearance and the volume of distribution (the independent pharmacokinetic parameters).

It is the integral of the plasma concentration-time profile from time zero to time infinity.

It has units of mass-time/volume.

The area under the curve after an iv administration is dependent on the administered dose and the total body clearance.