What are the different transport mechanisms of drug absorption?
What are the different transport mechanisms of drug absorption?
The mechanisms of drug absorption are, in order of their importance, (1) passive diffusion, (2) convective transport, (3) active transport, (4) facilitated transport, (5) ion-pair transport, and (6) endocytosis (pinocytosis).
What are the mechanisms of drug transport?
The five groups of drug transports are as follows: (1) organic ion transporter superfamily, (2) ATP-dependent transporter superfamily, (3) peptide transporter family, (4) organic anion transporting polypeptide family originated from liver and (5) amino acid-polyamine-choline transporter superfamily.
What is absorption explain active transport process of absorption?
Absorption describes the movement of a drug from where it is liberated into the bloodstream. Absorption may happen by one or more of these mechanisms: • passing through intercellular pores (spaces between cells); • passive transport (diffusion) through cell membranes; • active transport through cell membranes.
Which types of drugs get absorbed by ion pair transport?
Explanation: Ion-Pair Transport is the mechanism where absorption of drugs like quaternary ammonium compounds, sulphonic acids get absorbed. These drugs can get ionize at all pH conditions. These neutral complexes have lipophilicity and aqueous solubility for passive diffusion.
What route of drug absorption has the greatest bioavailability?
Intravenous (IV) drug administration is assumed to be the most dependable and accurate route for drug delivery, with a bioavailability of 100%. Absorption of drugs from tissues and organs (e.g., intramuscular, transdermal, rectal) can also be affected by development ( Table 73.2 ).
What is the major difference between facilitated diffusion and passive diffusion?
Table: Simple vs Facilitated Diffusion
| Simple Diffusion | Facilitated Diffusion |
|---|---|
| Example of simple diffusion: passive transport of small nonpolar molecules across the plasma membrane | Example of facilitated diffusion: passive transport of glucose and ions into and out of the cell |
What is ionized and unionized drugs?
Most drugs are weak acids or bases that are present in solution as both the ionized and unionized forms. Ionized molecules are usually unable to penetrate lipid cell membranes because they are hydrophilic and poorly lipid soluble. Unionized molecules are usually lipid soluble and can diffuse across cell membranes.
How are ionic ionizable drugs absorbed?
Ionized (or charged) drugs are not absorbed as efficiently as un-ionized drugs are. Practically speaking, this means that if taken orally, a drug that is a weak acid will be absorbed primarily in the acidic environment; whereas, a drug that is a weak base will be absorbed in the alkaline environment small intestines.
Which drugs absorb passive diffusion?
In general, lipid-soluble drugs, and drugs composed of smaller molecules, cross the cell membrane more easily and are more likely to be absorbed by passive diffusion.
