Pharmacology L4 Flashcards
How do drugs reach their target tissue
Through the blood
What are the general routes of drug administration
! Oral
! Intravenous
! Intra-arterial
! Intramuscular
! Subcutaneous
! Inhalation
! Topical
! Sublingual
! Buccal
! Rectal
What is ‘First-Pass Hepatic Elimination’
a pass through the liver, which may cause an
inactivation of the drug via biotransformation
What is the time course of drug concentation
Initially, drug conc is at its highest but it starts to decrease as time goes
Time course of drug concentration consists of:
-absorption
-distribution
-elimination
Absorption
Uptake from stomach and intestines into blood
Distribution(α-phase)
Systemic distribution into body tissues
Elimination (β-phase)
Elimination from body by biotransformation and excretion
External and internal barriers of the body to drug absorption
GI-tract barrier
Respiratory tract barrier
Oral mucosa barrier
Skin barrier
Blood-brain barrier
GI tract barrier
The intestinal epithelium with brush border serves as a barrier for orally administered drugs. The brush border contains microvilli that increase the surface area for absorption of nutrients and drugs.
Respiratory tract barrier
Cilia-bearing epithelium in the respiratory tract helps trap foreign particles and prevent them from entering the lungs
Oral mucosa barrier
The non-keratinized squamous epithelium lining the oral cavity provides a barrier for sublingual and buccal drug administration.
Skin barrier
The keratinized squamous epithelium in the skin provides a barrier for transdermal drug delivery
Blood-brain barrier
The pore-lacking CNS endothelia in the blood-brain barrier helps protect the brain from harmful substances.
Drugs may traverse biomembranes by
- Gradient diffusion
- Carrier transport
- Vessicular transport
- Surface receptor