Lipid based drug delivery system Flashcards
what are the three lipid nanoparticle classifications?
liquid lipid, solid lipid, solid/liquid lipids
what are some examples of liquid lipids?
nanoemulsions (NEs)
lipid nano capsules (LNCs)
what are some examples of solid lipids?
solid lipid nanoparticles (SLNs)
what are some examples of solid/liquid lipids?
nanostructure lipid capsules (NLCs)
what are the types of emulsions?
Oil-in-water (o/w)
water-in-oil (w/o)
what type of emulsion can be injected IV?
o/w only
what type of emulsion tend to deliver hydrophobic drugs?
o/w only
what type of emulsion tend to deliver hydrophilic drugs?
w/o only
what do nano emulsions contain?
oil -vegetable oil/medium chain triglycerides
water
stabiliser - phospholipids (often lecithin)
what are the methods to manufacturing nano emulsions?
- high energy methods
- ultrasound
- high shear homogenisation
- high speed homogenisation - low energy methods
- phase inversion method
whats the advantage of nano emulsions?
1.active targeting possible
- modify phospholipids
-modify functional PEG
2. lower viscosity vs coarse emulsion due to lower particle size
- better for injections
how do nanoemulsions destabilise?
thru…
Oswald ripening of polydispersed particle size
sedimentation/creaming
brownian motion
what type of emulsions are these examples?
-hydrophobic drugs
-vaccines
-parenteral nutrition
-hydrophobic drugs = o/w
-vaccines =w/o
-parenteral nutrition= o/w
why are nano emulsions used in vaccines?
as it’s an adjuvant, allowing a strong immune response
what are features of SLN?
solid at room temp. soften at body temp.
o/w
similar to NLCs
must be… biocompatible/biodegradable/GRAS (generally recognised as safe)
How are SLNs produced?
HIGH PRESSURE homogenisation
1. melt the lipid; add drug for drug loading particles
2. homogenisation
-hot (to emulsify and homogenise)
not good for thermaliable drugs
-cold using liquid nitrogen or dry ice (dispersed in water + surfactant =forms a suspension)
when is drug loading used in SLN? And how?
- hydrophobic drugs,
- macromolecules, water soluble low MW drugs - minimise affinity of drug in aq. phase by using cold homogenisation
what does the amount of drug loaded in SLN depend on?
- the solubility of the drug in the lipid melt
- the miscibility of the melted drug and lipid
- the structure of the solidified lipid matrix
- lipid polymorphism
which has better drug loading… NLCs or SLNs?
NLCs
why is using a hot temperature for homogenisation good?
increases the solubility of the drug in water
why is using a cold temperature for homogenisation bad?
solidified lipid from the core outwards, this will cause a burst drug release
when are NLCs preferred over SLNs?
- a low drug loading
- stop release of encapsulated drug during storage
what are the features of LNCs?
oil phase - medium chain triglycerides
aqueous phase - saline solution
surfactant - poly(ethylene glycol)660 + free PEG
-phospholipid
presence of a semi-solid rigid shell
when are LNCs mainly used?
hydrophobic drugs
what are the advantages of LNCs?
no special equipment needed
reproducible preparation
stable over time
useful for a wide range of therapeutics
low toxicity
solvent-free preparation
what are the dis-advantages of LNCs?
potential toxicity of excess surfactants
loading may require solvents
limited to 100nm particles
surfactant modification through PEGylation
