BIOAVAILABILITY
It is defined as the quantity and the rate of the drug that is absorbed and reaches the systemic circulation after non-vascular administration.
It is a measure of the fraction(F) of administered dose of a drug that reaches the systemic circulation in the unchanged form.
The bioavailability is 100% after intravenous injection.
But it is less after oral administration because----
(1) the drug may be incompletely absorbed.
(2) the absorbed drug may undergo first pass metabolism.
Bioavailability is affected by factors like,
(1) Physical properties of drug
(2) Dosage form
(3) Physiological factors
Differences in bioavailability are seen mostly with poorly soluble and slowly absorbed drugs.
Basic Simple Concepts Of Pharmaceutical Drugs - Pharmacy Topics With Easy Concepts - Drug Description with Administration, Distribution, Metabolism, Excretion, Pharmacological actions, Adverse Reactions.
No comments:
Post a Comment