Biomedical Engineering Reference
In-Depth Information
TABLE 11.3
Applications.of.Lipos
omes.in.Science
Disciplines
Applications
References
Physics
Aggregation.behavior,.fractals,.soft.and.high.strength.materials.
51
Biophysics
Permeability,.phase.transitions.in.two.dimensions,.photophysics.
52
Physical.chemistry
Colloid.behavior.in.a.system.of.well.deined.physical.characteristics,.
inter-.and.intra-aggregate.forces.
52
Biochemistry
Reconstitution.of.membrane.proteins.into.artiicial.membranes.to.
investigate.their.role.in.transport.mechanisms
53
Biology
Model.biological.membranes,.cell.function,.fusion,.recognition
54
11.2.1.2.1 In Medicine and Pharmaceuticals
Bioactive.substances.are.encapsulated.either.within.the.lipid.bilayer.or.in.the.aqueous.core.
of.the.liposome.according.to.their.properties,.and.form.liposome-drug.products..Use.of.
appropriate.drug.carriers.reduces.the.toxic.effect.of.drugs.and.modiies.their.absorption,.
distribution,.and.release.proile..These.are.important.because.they.can.change.the.drug's.
pharmacokinetics.(the.rate.of.transport.of.substances.administered.externally.to.a.living.
organism).and.biodistribution.in.the.body..Liposomal.drug.products.seem.to.meet.these.
features,.which.are.expected.of.suitable.drug.carriers.
The.advantages.of.loading.the.drug.into.the.liposome,.which.can.be.applied.as.(colloi-
dal).solution,.aerosol,.or.in.(semi)solid.forms,.such.as.creams.and.gels,.are.listed.below:
55
•. Increased. solubility. of. lipophilic. (amphotericin. B,. minoxidil). and. amphiphilic.
(anticancer.agent.doxorubicin.or.acyclovir).drugs
•. Sustained.release.of.systemically.or.locally.drug-administered.liposomes.(doxoru-
bicin,.cytosine.arabinose,.cortisones,.proteins,.or.peptides.such.as.vasopressin)
•. Decrease.toxicity,.such.as.nephrotoxicity,.cardiotoxicity,.and.neurotoxicity.(ampho-
tericin.B.has.reduced.nephrotoxicity,.and.doxorubicin.has.reduced.cardiotoxicity)
•. Site-speciic. targeting. by. ligands. attached. to. the. liposome. surface. (anticancer,.
antimicrobial,.and.anti-inlammatory.drugs)
•. Improved.transfer.of.hydrophilic,.charged.molecules.(chelators,.antibiotics,.plas-
mids,.and.genes.into.cells)
•. Enchanced.penetration.into.tissues,.especially.in.the.case.of.topically.applied.lipo-
somal.forms.(anesthetics,.corticosteroids,.and.insulin)
Today,. ive. liposomes. and. liposome-like. forms. for. intravenous. administration. have.
been.approved.and.are.being.marketed.for.clinical.use.in.the.European.Community..Four.
of.them.(Abelcet,.Amphotec,.DaunoXome,.and.Doxil).are.marketed.as.approved.drugs.in.
the. United. States.. Table 11.4. shows. characteristics. of. commercially. available. liposomal.
products.
56,57
In. addition. to. these. marketed. liposomal. products,. several. liposomal. drugs,. such. as.
liposomal.cyclosporin.A,.liposomal.nystatin,.liposomal.p-ethoxy.growth.receptor.bound.
protein-2. antisense. product,. liposomal. prostaglandin. E1. injection,. and. liposome-en-
capsulated.recombinant.interleukin-2.(1),.which.are.intended.to.treat.frequently.occur-
ring.diseases.such.as.cancer,.have.been.registered.in.the.United.States.as.orphan.drugs.
(FDA).
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