Drug solubilisation 3 Flashcards
(38 cards)
Amphiphilic polymers have a hydrophobic and hydrophilic domain. TRUE OR FALSE?
TRUE
In aqueous enviornments the amphiphilic molecules associate together to form non-covalent hydrophobic hydrophobic interactions. true or false?
true
How are polymeric nano aggregate (micelles) formed?
when the hydrophilic moeity remains in contact with aqueous environment and the hydrophobic moeity shields themselves
Amphiphilic polyemers have been known to form polymeric micellles, vesicles and nano-particles when in contact with aqueous environment. TRUE OR FALSE?
TRUE
Just like micelles, amphiphilic polymers encapsulate drug in the hydrophobic core therefore increasing its solubility. TRUE OR FALSE?
TRUE
what is the critical aggregation concentration?
- It is the lowest concentration whereby polymeric micelle is formed in an aqueous environment
what is CAC affected by?
- The addition of electrolytes
- The nature and structure of the hydrophobic group
what are the advantages of polymeric micelles over traditional surfactants micelles?
- CAC is lower
- Size of self-assemblies is smaller (30-100nm)
- Drugs can enter cell via endocytosis and become encapsulated
- Polymeric structures mimic naturally occuring transport system
- The nanoscopic isze of micelle enables quick and easy sterilisation
- Polymeric ration can be as little as 5:1 which increases efficiency and decreases toxicity
The micelle protects the drug from chemical degredation and metabolism down its journey to the desired target site. TRUE OR FALSE?
TRUE
what are the four classes of amphiphilic polymers?
- Block polymers
- Star shaped polymers
- Dendrimers
- Graft polymers
Block polymers are fabricated from the polymerization of two or more types of monomer units. TRUE OR FALSE?
TRUE
In aqueous solution, amphiphilic block polymers form polymeric micelles. TRUE OR FALSE?
TRUE
what is the hydrophobic moeity of the block polymers composed of?
- Biodegradable and biocompatible monomers e.g polyesters
what is the most common hydrophilic segment for block copolymer?
- PEG
Amphiphilic graft polymers consist of a homo polymer as the backbone, where the hydrophobic pendant groups are grafted to form a comb like structure. true or false?
true
what is the hydrophobic pendant groups of a comb shaped polymer consist of?
- Homopolymers
- Copolymers
- Small molecular weight hydrophobic molecules
the hydrophilic corona stabilises the hydrophobic core self-assembly. TRUE OR FALSE?
TRUE
Graft molecules can aggregate through intermolecular and intramolecular aggregation. TRUE OR FALSE?
TRUE
what are the advantages of graft polymers over block polymers?
- Lower CAC than block polymers
- Capable of higher solubilisation than block polymers
- Lower excipient to drug ratio
- More efficient system
- forms smaller aggregates in aqueous media
what are star shaped amphiphilic polymers?
- They are made up of 3 or more linear polymer chains linked to the central polymeric core
nano aggregates of the star shaped copolymer posses smaller size compared to linear polymers of the same MW. TRUE OR FALSE?
TRUE
star shaped polymers form unimolecular micelles that are more stable than block polymers. TRUE OR FLASE?
TRUE
The physical properties of the polymer can be changed by changing the chemical structure. TRUE OR FAKSE?
TRUE
Describe the three methods of drug loading for amphiphilic nano drugs particles?
- Solvent evaporation - polymer and drug are dissolved in organic solvent, solvent is removed and residue is re-dissolved in water and filtered
- Dialysis - polymer and drug is dialysed against water, the solvent and drug is leaks out into the surrounding media
- Sonication - polymer and drug are sonicated in queous environemnt, the resulting solution is filterted to obtain free drug
