Carrier mediated transport is both rapidly reversible and saturable.
True.
A drug weighing up to ___KD may be passively diffused through the capillary wall.
60
% ionized for an acid: (equation)
100/ (1= antilog (pKa-pH))
% ionized for a base: (equation)
100/ (1+ antilog (pH - pKa))
When "like" is in "like" the drug is ?
non-ionized
When "like" is in "unlike" the drug is ?
ionized
Concentration ratio equation for an acid:
pH-pKa= log (conc. ionized)/(conc. noni)
Concentration ratio equation for a base :
pH-pKa= log (conc. noni)/(conc. ionized)
What 3 events must an orally administered drug undergo before entering the systemic circulation?
1) release of drug from solid dosage form
2) transport across the the GI mucosal barrier
3) passage through liver
What is the rate limiting step of oral administration?
Dissolution
What is the principle site of orally administered drugs?
small intestine.
What is bioavailability?
The rate and extent to which a drug administered in a particular dosage form enters the systemic circulation.
Factors influencing bioavailability include:
poor dissolution of the drug product
instability of inactivation of the drug
poor passage of the drug through the mucosa
drug metabolism in the intestine or liver
When are two drugs bioequivalent?
when the rates and extents of absorption of the active ingredient in the 2 products are not significantly different under suitable test conditions (generic vs trademarked)
What is Volume of Distribution?
Volume of fluid that would be required to contain the amount of drug in the bosy if it were uniformy distributed at a concentration equal to that of plasma. (theoretical)
Body Clearance:
the volume of plasma cleared of the drug by various elimination processes per unit of time.
Class I drugs:
Dose less then available binding sites
Class II drug:
Dose greater then available binding sites.
When Phase II (Synthetic) reactions take place?
When a drug or phase I metabolite contains a chemical group suitable for combining with a natural compound to form a readily excreted polar metabolite.
Decreased hepatic blood flow _______ the rate of metabolism.
reduces
Decreased serum protein ________ drug availability for metabolism.