Module 4 Flashcards
Pharmacokinetics 2: Drug Absorption, Distribution, Metabolism, and Elimination
Volume of fluid in which the drug distribute itself
throughout the body at the same concentration as in
the plasma.
Volume of distribution
The range between the MEC and the MTC is called the
Therapuetic range or therapeutic window
Is the pH at which half the drug (weak electrolyte) is in its ionized form
pKa
Henderson-Hasselbach Equation
log [protonated] / [unprotonated] = pKa - pH
The time required for the drug [plasma] to fall by 50%.
Plasma half-life
Accounts for the rate of drugs eliminated or disposed by all routes in relation to the drug concentration in plasma.
Drug clearance
A weak basic drug will be easily absorbed in a ___________ environment
Alkaline
The drug’s initial distributive /bioavailability state is called
Onset
Which drug has very limited dissolution
Tablets
P coefficient <1
Has a lower partition coefficient and highly distributed in hydrophilic compartments
Which drug has the best dissolution
Small particles
True or false. Weak acid drugs will be charged at neutral pH
False. It needs to be in an acidic environment to be charged.
The ratio of non-ionized to ionized form at each pH is known by
Henderson-Hasselbach Equation
Volume of distribution formula
Vd=Dose /Initial plasma concentration
Bioavailability whereinn enteral and paranteral forms of the same drug can be compared
Absolute
The drug has a narrow and steep AUC is considered to be a drug with
Narrow margin of safety
A less affinity drug to plasma protein means they are
Easily unbound and has higher tissue distribution
These are agents that can rapidly be absorbed
Particle size and wetting agents
Plasma half-life formula
T1/2 = log of 2 (Vd)/ Cl
Is the ratio of concentrations of a compound in a mixture of two immiscible solvents at equilibrium.
Partition coefficient
Describes the absorptive nature of the drug depends on their chemical nature, either acidic (weak acidic drugs) or alkalinic (weak basic drugs)
Distributive (D) coefficient
Formula of drug clearance
Cl = coefficient for CLCr of drug (creaCL/pt.weight) + units of Clcr
The AUC of the drug will also reflect the drug activity which is called
Duration of area
Rate and extent of entry of the drug
substance from the administration site until
it reaches the systemic circulation (blood).
Absorption
Are able to form conjugates with drugs
or hydrolyze and oxidize drugs
Hepatic enzymes
The drug concentration at which is expected to give it therapeutic effect or drug benefit
Minimum effective concentration
Which phase is the metabolic phase for xenobiotic drugs
Phase 2
These agents increases absorption in terms of its form
Salt
P coefficient of >1
Has higher partition coefficient and prefers to be distributed in lipid bi-layered cell membrane
Indicates the rate and extent of the absorbed active drug that reaches the systemic circulation
Bioavailability
The type of drug kinetics that depends on drug concentration and the rate of elimination is directly proportinal to the concentration of the drug
Linear kinetics
Drugs that are considered as bound drugs and has high bioavailability
Drugs that bind with plasma protein
What kind of drug has a P coefficient of >1
Lipophilic drug
These are agents which delay dispersion of drug and promote binding during drug absorption
Excipients
What kind of drug has a P coefficient <1
Hydrophilic drugs
The type of drug kinetics that is independent from drug dose-plasma concentration and rate of drug elimination is unpredictable
Non-linear kinetics
A weak acid will be uncharged and a weak alkaline will be charged in the stomach due to
The stomach mucous having an acidic environment
The drug concentration at which beyond the upper limit can cause drug over dosaging and form toxic effect
Maximum tolerated concentration
Is a gathered plasma data of a given population, when the drug has a tested value or concentration versus the reference concentration.
Relative availability
Which phase is the metabolic phase primarily for renal elimination route
Phase 1
Which drug has limited dissolution
Granules
A weak acid drug will be easily absorbed in a ___________ environment
Acidic
A wide margin of safety drug is said to have
A wider AUC and a longer therapuetic window
