Drug Delivery Basics Flashcards
Methods to improve drug aqueous solubility (7)
Reduce particle size
Salt formation
Soluble prodrug
Polymorphic form
Amorphous form
Solvate
Formulation factors
Extended Release
Drug is released slowly over time
Sustained release
Drug is released slowly, rate is controlled by delivery system
Controlled Release
Drug is released at constant rate, so that plasma concentration does not vary with time
Delayed release
Drug released at a time other than after administration
Targeted release
Drug delivered to a desired target tissue, without exposing entire body to a similar dose
Pulsatile release
Drug delivered in bursts, at predetermined time intervals
These drugs often have high first pass effect
‘New biotherapeutics’ definition
Molecules being developed through biotechnology and molecular biology
Advantages of protein therapeutics
Good efficacy
Good safety
Predictable metabolism
Shorter time to market
Highly selective and potent
Disadvantages of protein therapeutics
Not chemically or physically stable
Prone to hydrolysis and oxidation
Cost
Low membrane permeability
Not orally available
Short half life
Endopeptidase cleavage
A peptidase that catalyses the cleavage of internal peptide bonds in a protein
Exopeptidase cleavage
A peptidase that catalyses the cleavage of terminal peptide bonds in a protein
Problems with protein enzymatic degradation
Proteases are present everywhere in the body
Degradation of a single peptide bond can destroy a proteins biological activity
Several bonds in a protein are usually prone to attack
Each peptide bond can be degraded by a range of enzymes
