What is the unit of rate constant for second order reaction?
Unit of reaction rate (r) is moles per liter per second (mol. L-1. s-1) and the unit of second order rate constant is M-1.
What does 2nd order reaction mean?
: a chemical reaction in which the rate of reaction is proportional to the concentration of each of two reacting molecules — compare order of a reaction.
What is the rate constant for zero-order reaction?
Unlike the other orders of reaction, a zero-order reaction has a rate that is independent of the concentration of the reactant(s). The rate law for a zero-order reaction is rate = k, where k is the rate constant.
What is the half life of a zero order reaction?
For a zero order reaction (Half life decreases with decreasing concentration.) For a 1st order reaction (Half life is constant.) For a second order reaction (Half life increases with decreasing concentration.)
Why are most drugs eliminated in first-order?
FIRST-ORDER KINETICS For most drugs, we need only consider first-order and zero-order. Most drugs disappear from plasma by processes that are concentration-dependent, which results in first-order kinetics. With first-order elimination, a constant percentage of the drug is lost per unit time.
Why does a drug with zero-order kinetics not have a fixed half life?
This does not work if the elimination of the drug occurs at a constant rate which is independent of concentration. Thus, in zero-order kinetics of elimination the concept of half-life becomes meaningless because the drug concentration does not decrease by half with every predictable time interval.
Can zero order drugs reach steady state?
On continuous or repeated administration, approximately 4 to 5 half-lives are required to reach steady state. In contrast, for drugs that exhibit zero-order kinetics (saturable elimination), half-life generally increases with dosage because a constant amount (not proportion) of drug is eliminated.
How do you calculate drug steady state?
The time to reach steady state is defined by the elimination half-life of the drug. After 1 half-life, you will have reached 50% of steady state. After 2 half-lives, you will have reached 75% of steady state, and after 3 half-lives you will have reached 87.5% of steady state.
What is the steady state level of a drug?
Steady-state concentration is the time during which the concentration of the drug in the body stays consistent. For most drugs, the time to reach steady state is four to five half-lives if the drug is given at regular intervals—no matter the number of doses, the dose size, or the dosing interval.