What is zero order kinetics in drugs?
Definition. Sometimes a drug is absorbed at essentially a constant rate, called zero-order absorption. Zero-order kinetics is described when a constant amount of drug is eliminated per unit time but the rate is independent of the concentration of the drug.
What does zero order metabolism mean?
Lesson Summary. To summarize, zero order kinetics means a drug’s metabolism can be predictable: the body will break it down at the same rate until all of it is gone, unlike first order kinetics where the rate at which a drug is broken down is proportional to the concentration given.
What are zero order kinetics of eliminations?
The fundamental difference between zero and first-order kinetics is their elimination rate compared to total plasma concentration. Zero-order kinetics undergo constant elimination regardless of the plasma concentration, following a linear elimination phase as the system becomes saturated.
What is zero order reaction give example?
Reaction in which concentration of the reactants do not change with time and the concentration rates remain constant throughout are called zero order reactions. A→Product. Example: H2+Cl2hv 2HCl.
What are the characteristics of zero order reaction?
A zero-order reaction, unlike the other orders of reaction, has a rate that is independent of the reactant concentration (s). As a result, increasing or decreasing the concentration of the reacting species has no effect on the reaction rate.
What is first order kinetics and zero order kinetics?
In zero-order kinetics, the rate of reactions of chemical reactions are independent of the concentration of reactant. In first-order kinetics, the rate of reactions of chemical reactions are dependent on one of the concentrations of reactants.
What are the five primary mechanisms of particle deposition?
The primary aerosol deposition mechanisms may include inertial impaction, sedimentation, diffusion, interception, and electrostatic effects (6,8,9). The contribution of these deposition mechanisms is a function of particle size and flow rate in a given region of respiratory tract.
What are the mechanisms of particle deposition?
The main mechanisms are inertial impaction, gravitational sedimentation, and Brownian diffusion. To a lesser extent, other mechanisms such as mixing induced by turbulent flows, electrostatic precipitation, and, in the case of elongated particles (i.e., fibers), interception can also cause aerosol deposition (Fig. 1).
What are the four stages of drug disposition?
Drug disposition describes how drugs enter and exit the body and explains how concentrations in the body change over time (Figs. 45.2 and45.3). Four basic processes explain the disposition of drugs through the body: absorption, distribution, metabolism, and excretion.
What is zero order reaction explain with example?
What are the examples of zero-order reaction?
The rate of the reaction is related to the reactant’s concentration….Examples
- The reaction of hydrogen with chlorine is also known as a Photochemical reaction.
- Decomposition of nitrous oxide on a hot platinum surface.
- Decomposition of NH3 in the presence of molybdenum or tungsten is a zero-order reaction.
What is the difference between zero first and second-order reactions?
A zero-order reaction proceeds at a constant rate. A first-order reaction rate depends on the concentration of one of the reactants. A second-order reaction rate is proportional to the square of the concentration of a reactant or the product of the concentration of two reactants.