Search results
Results from the WOW.Com Content Network
In situ IR may be classified as an integral technique as the primary data collected are proportional to concentration vs. time. [2] From these data, the starting material or product concentration over time may be obtained by simply taking the integral of a polynomial fit to the experimental curve. [3]
Because ln 2 equals 0.693, the half-life is readily calculated from the elimination rate constant. Half-life has units of time, and the elimination rate constant has units of 1/time, e.g., per hour or per day. An equation can be used to forecast the concentration of a compound at any future time when the fractional degration rate and steady ...
The absorption rate constant K a is a value used in pharmacokinetics to describe the rate at which a drug enters into the system. It is expressed in units of time −1. [1] The K a is related to the absorption half-life (t 1/2a) per the following equation: K a = ln(2) / t 1/2a.
D t = time required; the unit of time used is the same as is used for Q; V = air or gas volume of the closed space or room in cubic feet, cubic metres or litres; Q = ventilation rate into or out of the room in cubic feet per minute, cubic metres per hour or litres per second; C initial = initial concentration of a vapor inside the room measured ...
Fick's first law relates the diffusive flux to the gradient of the concentration. It postulates that the flux goes from regions of high concentration to regions of low concentration, with a magnitude that is proportional to the concentration gradient (spatial derivative), or in simplistic terms the concept that a solute will move from a region of high concentration to a region of low ...
The steady state approximation, [1] occasionally called the stationary-state approximation or Bodenstein's quasi-steady state approximation, involves setting the rate of change of a reaction intermediate in a reaction mechanism equal to zero so that the kinetic equations can be simplified by setting the rate of formation of the intermediate equal to the rate of its destruction.
A more intuitive characteristic of exponential decay for many people is the time required for the decaying quantity to fall to one half of its initial value. (If N(t) is discrete, then this is the median life-time rather than the mean life-time.) This time is called the half-life, and often denoted by the symbol t 1/2. The half-life can be ...
A graph depicting a typical time course of drug plasma concentration over 96 hours, with oral administrations every 24 hours. The main pharmacokinetic metrics are annotated. Steady state is reached after about 5 × 12 = 60 hours.