1. Absorption Flashcards
what is PHARMACOKINETICS the STUDY OF
what the BODY DOES TO A DRUG
only SMALL PORTION of the DRUG reaches the SITE OF ACTION. what happens to the rest?
either METABOLISED or ELIMINATED
drug by ORAL ADMINISTRATION passage to SYSTEMIC CIRCULATION:
drug in solution
released in INTENSTINES lumen, passes intestines wall to the LIVER
(to systemic circulation)
drug by ORAL ADMINISTRATION passage to SYSTEMIC CIRCULATION:
DIRECTLY to Systemic Circulation
- BYPASSES other organs etc
an understanding of PHARMACOKINETICS should help us to:
- design DOSAGE Regimens
- PERSONALISE/STRATIFT DOSAGE Regimen based on PATIENT’S CHARACTERISTICS
- DETERMINE what is wrong when a patient FAILS to RESPOND to TREATMENT
- find out why a Drug has CAUSED TOXICITY
- Understand the MECHANISMS of DRUG INTERACTIONS
ROUTE of DRUG ADMINISTRATIONS:
(dependent on DRUG and TARGET AREA)
- ORAL
- SUBLINGUAL
- RECTAL
- other Epithelal surfaces:
SKIN, CORNEA, VAGINA, NASAL MUCOSA - INJECTION
- INHALATION
what is TOPICAL ADMINISTRATION
ON TO the SKIN
what is SYSTEMIC ADMINISTRATION
INTO the BODY
what is SYSTEMIC ADMINISTRATION: ENTERAL administration
GI TRACT ROUTE
what is SYSTEMIC ADMINISTRATION: PARENTAL administration
NON-GI TRACT ROUTE
eg. injection, inhalation
ORAL administration: what is Fa
Fraction of the dose AVAILABLE FOR ABSORPTION
ORAL administration: what is Fg
Fraction of the dose ESCAPING INTESTINAL METABOLISM
(ability to permeate intestinal wall)
ORAL administration: what is Fh
Fraction of the dose ESCAPING HEPATIC FIRST PASS METABOLISM
(penetration through first pass metabolism)
what is FIRST PASS METABOLISM
The degree of metabolic breakdown of an orally administered drug that occurs in the INTESTINE or LIVER BEFORE it reaches the SYSTEMIC CIRCULATION
How is PENETRATION and Cmax (max plama conc.) after INTRAVENOUS ADMINISTRATION
IMMEDIATE
Cmax at 0 Hours
