What is extravascular route?
extravascular (for example, oral, intramuscular, sub- cutaneous, pulmonary or rectal) in which there is an. absorption phase prior to the drug appearing in the. systemic blood.
What is a one-compartment model?
The one-compartment open model is the simplest way to describe the process of drug distribution and elimination in the body. This model assumes that the drug can enter or leave the body (ie, the model is “open”), and the entire body acts like a single, uniform compartment.
What is first-order absorption?
First-order input means the absorption rate is proportional to the amount (or concentration) of drug at the absorption site. Typically this means that the absorption rate is higher imme- diately affer the dose is given and the rate then decreases as drug is absorbed.
Is one-compartment model a first-order?
One-compartment model with first-order elimination. The differential equations can be used to simulate the concentration or amount of drug in the body at different time points with different drug administration regimes.
Is intramuscular extravascular?
The predominant route of drug administration is extravascular, such as oral, peroral, intramuscular, subcutaneous, intrathecal, intradermal, rectal, or topical.
What is the meaning of extravascular?
: not occurring or contained in body vessels extravascular tissue fluids.
What is a 2 compartment model?
Definition: The two compartment open model treats the body as two compartments. Input and output are from the central compartment. Mixing occurs between the two compartments.
How many types of compartment models are there?
While the one-compartment model approximates the whole body as a single compartment by assuming that the drug concentration is uniformly distributed and is eliminated by a first-order process, the three-compartment model features (i) a central compartment model that corresponds to plasma, (ii) a rapidly-equilibrating …
What is the difference between 1st and zero order rate reactions?
The main difference between first order and zero order kinetics is that the rate of first order kinetics depends on the concentration of one reactant whereas the rate of zero order kinetics does not depend on the concentration of reactants.
What are the limitations of one compartment model?
A single compartment model is the least accurate, as it assumes a homogeneous distribution of the drug in the body.
What is a two-compartment model?
Pharmacokinetic two-compartment model divided the body into central and peripheral compartment. The peripheral compartment (compartment 2) consists of tissues where the distribution of the drug is slower.
How is the volume of the intravascular compartment regulated?
The volume of the intravascular compartment is regulated in part by hydrostatic pressure gradients, and by reabsorption by the kidneys. The interstitial compartment (also called “tissue space”) surrounds tissue cells. It is filled with interstitial fluid, including lymph.
How are the interstitial and intravascular compartments related?
When illnesses upset the balance, electrolyte imbalances can result. The interstitial and intravascular compartments readily exchange water and solutes, but the third extracellular compartment, the transcellular, is thought of as separate from the other two and not in dynamic equilibrium with them.
Can a one compartment model describe plasma absorption?
A large number of plasma concentration-time profiles can be described by a one-compartment model with first-order absorption and elimination. However, under certain conditions, the absorption of some drugs may be better described by assuming zero-order (constant rate) kinetics.
When is a drug administered by the extravascular route?
Extravascular Administration When a drug is administered by extravascular route (e.g. oral, i.m., rectal, etc.), absorption is a prerequisite for its therapeutic activity. Factors that influence drug absorption have already been discussed in chapter 2.