What does plasma concentration of a drug mean?
“Maximum plasma concentration” means the highest drug concentration after administration, while “a time to maximum plasma concentration” means the time at which the highest drug concentration is observed.
Why is plasma drug concentration important?
Plasma concentration monitoring of most antiarrhythmic agents is of value for certain specific purposes: to determine compliance to antiarrhythmic therapy, to detect and analyze possible drug interactions, to assess the benefit to risk ratio for increasing the dose of a particular antiarrhythmic agent, to maintain a …
How do you calculate plasma concentration?
Loading dose (mg) = [Cp (mg/L) x Vd (L)] / F
- Cp represents the desired plasma concentration of drug.
- Vd represents the volume of distribution.
- F represents the bioavailability of drug (IV administration = 1)
What is plasma concentration time curve?
The area under the blood (or plasma) concentration–time curve reflects the amount of a xenobiotic that has effectively reached the systemic circulation and as such is influenced both by the degree of bioavailability and by the rate at which a xenobiotic is removed from the body.
What happens if plasma concentration increases?
Subsequent higher doses increased sedation, all pressures, and calculated vascular resistance, and resulted in significant decreases in heart rate, cardiac output, and stroke volume. Recall and recognition decreased at a dose of more than 0.7 ng/ml.
What are the main factors that determine plasma concentration?
Likewise, plasma levels will depend on dosage, time and route of drug administration, the bioavailability of the drug and time of blood sampling. In addition, absorption, distribution, metabolism, excretion and concurrent drug administration may profoundly affect plasma drug concentrations.
What is Kel in pharmacokinetics?
The elimination rate constant (abbreviated as kel, k10, and sometimes ke) is the first order rate constant describing drug elimination from the body. This is an overall elimination rate constant describing removal of the drug by all elimination processes including excretion and metabolism.
What does peak concentration mean?
Peak Concentration. A pharmacokinetic measure used to determine drug dosing. Cmax is the highest concentration of a drug in the blood, cerebrospinal fluid, or target organ after a dose is given.
What are the parameters that describe the plasma concentration time curve and are useful in assessing the bioavailability?
Area Under the Curve(AUC): AUC is expressed in mcg/ml * hours. It is the most important parameter in evaluating the bioavailability of a drug from its dosage form as it represents the extent of absorption.
When does plasma concentration increase?
Plasma concentration of CT-1 is elevated in patients with both stable and unstable angina pectoris as compared with that in control subjects, and plasma CT-1 concentration is more increased in unstable angina pectoris than in stable angina pectoris [100].
What happens when plasma concentration decreases?
Decreased plasma protein binding leads to an increase in free plasma fraction causing an increase in volume of distribution and a shorter elimination half life. The increase in the apparent volume of distribution and the shorter elimination half life cause a decrease in total plasma concentration.
What is K in pharmaceutics?
The elimination rate constant K or Ke is a value used in pharmacokinetics to describe the rate at which a drug is removed from the human system. It is often abbreviated K or Ke. It is equivalent to the fraction of a substance that is removed per unit time measured at any particular instant and has units of T−1.
What is meant by ‘plasma concentration of drug’?
The concentrations of drug in each plasma sample are plotted on an ordinary graph paper against the corresponding time at which the plasma samples were collected. As the drug reaches in systemic circulation, plasma drug concentration will rise to a maximum. The absorption of a drug is more rapid than its elimination. As the drug is being absorbed into systemic circulation, the drug is distributed to all the tissues in the body and is also simultaneously being eliminated.
What is steady state plasma concentration?
What is steady state plasma concentration 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
What are the characteristics of a plasma?
What are characteristics of plasma? Like gases, plasmas have no fixed shape or volume, and are less dense than solids or liquids. But unlike ordinary gases, plasmas are made up of atoms in which some or all of the electrons have been stripped away and positively charged nuclei, called ions, roam freely.
What is contained in plasma?
Plasma itself consists of 92% water. Vital proteins involved in many functions such as blood clotting, fighting infections, and transporting substances make up 7% of plasma. The remaining 1% contains mineral salts, sugars, fats, hormones, and vitamins.