PHARMACOKINETICS & THE LADMER SYSTEM Flashcards
The drug’s uptake from the site of administration to the systemic circulation
ABSORPTION
The drug’s movement to various sites after entering systemic circulation
DISTRIBUTION
The drug’s conversion to metabolites
METABOLISM
The drug’s removal from the body
EXCRETION
The release of active ingredient from its dosage form.
LIBERATION
Rate-limiting step in absorption of solid dosage forms and consequently onset, intensity, and duration of action of the drug
Dissolution
Factors that influence the dissolution rate (3)
Surface Area
Salt Forms
State of Hydration
Factors that influence the dissolution rate (2)
Crystal Form
Amorphous Drug Form
The proportion of a drug that is delivered to its site of action in the body
Bioavailability
RATE and EXTENT of DRUG entry into the systemic circulation
ABSORPTION
The large surface area of the gastro-intestinal tract is due to the presence of?
Microvilli
Location of microvilli
Small intestines. (Duodenum)
Essential for absorption of weakly acidic drugs
STOMACH
Not good as an absorption site
Stomach
Essential organ for weakly basic drugs
Intestine
Basic (pH 6-8); depending on part
Intestine
Highly acidic (pH 1.5-2) (pH 2-6; fasting pH)
Stomach
Covered with thick mucus layer
Stomach
Exception to Liberation are Oral Solutions, Parentals, TDDS (T/F)
True
The Smaller the molecule the larger the surface area (T/F)
True
Salt forms dissolve less than free form drugs (T/F)
False (dissolve much readily)
Amorphous Drugs are short acting compared to crystalline (T/F)
True
The higher the blood supply the shorter extent / slower absorption (T/F)
False (Greater extent / Faster Absorption)
It has the largest absorbing surface at 120 - 200 sq. m
Gastro-Intestinal Tract (GIT)
Time it takes for the stomach to empty its contents
Gastric emptying rate
Has the greatest capacity for the absorption of drugs from the GI tract
Duodenum
