Lecture 9 - Liposomes Flashcards
What does the stratum corneum do?
Prevents entry of both toxic and topical agents
Define nanoparticles
solid colloidal particles
consist of macromolecular molecules
can be used as drug carries
Define ethosome
Soft lipid vesicles composed of phospholipids, water and ethanol at relatively HIGH concentrations
What are edge activators?
Destabilise the lipid bilayers of the SC and increase in deformability by lowering interfacial tension of lipid bilayers
Define binary ethosomes and give examples
Adding another type of alcohol to the classical ethosomes
PG and iPA
Define transethosomes
Contains basic components of classical ethosomes and an additional compound, such as a penetration enhancer or an edge activator (surfactant) in their formula
Define nanostructured lipid carriers (NLC)
2nd generation of lipid nanoparticles
overcome the solid lipidnanoparticles
solid and liquid lipids
Define solid lipid nanoparticles
1st generation of LNs
increased adhesiveness to surfaces
controlled occlusion effect
increased skin hydration
What are the disadvantages of SLN?
Decreased loading capacity
Expulsion of drug during storage
Advantages of lipid nanoparticle carriers
Low toxicity
small particle size
increased skin hydration
enhance stability of liable compounds
physical sunscreen on their own
reduce skin irritation
Define liposomes
Lipid structures made of phospholipids (and cholesterol)
Define niosomes
BIlayered structures made of non-ionic surfactant and cholesterol
What are the advantages and disadvantages of niosomes?
able to entrap wide range of chemicals
less toxic than carriers with ionic surfactants
limited shelf life
time consuming and specialised required for the penetration process
Define nanoemulsions
Isotropic dispersed systems of 2 immiscible liquids - o/w or w/o nanoemulsions
What are the advantages and disadvantages of nanoemulsions?
Both hydrophobic and hydrophilic drugs can be applied
solubilisation/ extraction of SC lipids - thereby decreasing resistance for drug transport
greater and extended cellular penetration
raised efficacy due to increasing surface to volume ratios
non-toxic and non-irritant
kinetically stable
stability problems
