What are the pharmacokinetics of aspirin?
Pharmacology/Pharmacokinetics Aspirin is rapidly absorbed in the upper gastrointestinal (GI) tract and results in a measurable inhibition of platelet function within 60 minutes. This antiplatelet effect is associated with prolongation of the bleeding time and inhibition of TXA2-dependent platelet aggregation.
What is steady state in pharmacokinetics?
Steady-state concentration (Css) occurs when the amount of a drug being absorbed is the same amount that’s being cleared from the body when the drug is given continuously or repeatedly. Steady-state concentration is the time during which the concentration of the drug in the body stays consistent.
How do you calculate the steady state concentration of a drug?
This parameter can be calculated based on the steady state definition where the rate of input is equal to the rate of elimination. Thus, the average concentration at steady state is simply the total exposure over 1 dosing interval divided by the time of the dosing interval.
When does a drug reach steady state?
Following repeated administration of a drug, a steady-state is reached when the quantity of drug eliminated in the unit of time equals the quantity of the drug that reaches the systemic circulation in the unit of time.
Is aspirin metabolized by CYP450?
Aspirin is metabolized by three key enzymes, UDP-glucuronosyltransferase 1A6 (UGT1A6), cytochrome P450 2C9 (CYP2C9), and N-acetyl transferase 2 (NAT2). Each of these enzymes is known to have genetic polymorphisms. No significant association was found with the other two enzymes, UGT1A6 and NAT2.
What is structure of aspirin?
C₉H₈O₄Aspirin / Formula
What is steady state equation?
A steady state for a differential equation is a solution where the value of y does not change over time. For example, consider an economy with capital and depriciation.
How do you calculate Ke pharmacokinetics?
Volume of Distribution, Clearance, and KE
- Formula | Volume of Distribution = Total Dose / Concentration.
- VD = 2,000 / 600 = 3.33 L.
- Formula | VD = CL / KE.
- (2,000 / 600) = 0.05/ KE = 0.015 hr (-)
- Formula | Half Life = 0.693 / KE.
- Half Life = 0.693 / 0.015 = 46.2 hours.
What determines the peak concentration of a drug?
Time of maximum concentration/time of peak concentration is the time required for a drug to reach peak concentration in plasma. The faster the absorption rate, the lower is the tmax.
How is aspirin metabolized?
Let’s look at aspirin as example of a drug being metabolised. Aspirin undergoes phase 1 hydrolysis to salicylic acid. In phase 2 it is congugated with either glycine or glucoronic acid forming a range of ionised metabolytes that can then be excreted in the urine.
What is the MOA of aspirin?
Aspirin is non-selective and irreversibly inhibits both forms (but is weakly more selective for COX-1). It does so by acetylating the hydroxyl of a serine residue. Normally COX produces prostaglandins, most of which are pro-inflammatory, and thromboxanes, which promote clotting.
What is the pharmacokinetics of aspirin?
Clinical pharmacokinetics of aspirin Aspirin is very rapidly absorbed from the gastrointestinal tract when administered as a solution, and somewhat more slowly when administered in tablets. It is rapidly hydrolyzed in the body to salicylic acid; the plasma concentration of the latter must be maintained within a relatively narrow range …
What is the hydrolysis of aspirin?
1 Aspirin is partly hydrolyzed to salicylic acid during absorption. Absorbed aspirin is rapidly hydrolyzed systemically.
What are the therapeutic and toxic drug levels for aspirin?
Therapeutic Index and Toxic Doses Therapeutic drug levels for aspirin are 150 to 300 mcg/mL (salicylate). Toxic Levels: Greater than 300 mcg/mL Timing: 1 to 3 hours after the dose
What is the pH level of aspirin absorption?
Aspirins absorption is pH sensitive at the level of the small intestine. Absorption is higher through the small intestine than the stomach for the same pH range. At pH 3.5 or 6.5, aspirin’s intestinal absorption is greater than the gastric absorption of the compound.