von Patricia Nicolas Vor 6 Jahren
850
Mehr dazu
tissue distribution
vesicle clearance rate
low stability in blood and interstitial fluids
Antifoaming agent 2-3
w/o emulsifying agents 3-6
wetting and spreading agents 7-9
o/w emulsifying agents 8-16
detergents 13-15
solubilizing agent 15-18
**emulsifier must be more soluble in continuous phase
surfactant as emulsifying agent 8-18
7-9 surfactant act as wetting agent
3-6 W/O
8-18 O/W
poor as a surfactant
may be water soluble or insoluble depending on functional group
water insoluble
fatty acid
glycerol esters
fatty alcohols
water soluble
polyoxyethylene groups
stability
good compatibitlity
no charge
isoelectric point
behave similar to nonionic surfactant
both positive and negative charges upon full ionization
carboxylate
ammonium group
example
alkyl betaine
glycine
Benzylalkonium chloride ( BAC/BAK)
function in protonated state
positive charge
quaternary ammonium
retains charge over the entire pH range
amines
ph depended
nitrogen atom
above the pKa will ionize
if countering are mono valiant most likely not soluble
if the counter ion are sodium or potassium= water soluble
in a basic solution acid are negatively charge
Sodium Lauryl sulfate (SLS)
most common surfactant
emulsifying agent
wetting agent
most widely used class
negative charge
phosphate
sulfonate
sulfate
caboxylate
premature infant have not enough lung surfactant= death
decreasing the surface tension
decreases pressure inside alveoli
prevents collapse of alveoli
covers the surface of alveoli contacted with air
cationic and ionic absorb onto bacteria surface --> leaking of lipid cell membrane--> bacterial death
IM/ Subq: liposome get into the lymphatic system; vaccine delivery
reaction with antibodies to be phagocytize into the liver and spleen allowing for passive targeting of these sites
surface activity
this is to achieve minimum energy state
amphiphilic orientation to remove the hydrophobic group from the aq. environment
lowering the surface tension
at the surface particle are not completely surrounded which results in a net inward force attraction exerted on molecules at the surface by the molecules in the bulk solution
contracted surface = minimum free energy
thus liquid surface contracts and form a sphere spontaneously
increase in hydrophobic chain
bigger size
low CMC
More surfactant= less surface tension
surfactant associating to itself encapsulating and forming a sphere
hydrophobic groups withdrawing form the aqueous phase
concentration that micelles form to attain minimum free energy state
too much surfactant requires energy to keep all in a solution thus to lower energy form micelle = Entropic Effect
high = poor wettability > 90
low = good wettability <60
