Liposomes & Nanotech

What are the current problems with drug delivery?

-poor water solubility (poor bioavailability) -high initial release (burst) -loss of bioactivity -delivery to non-targeted sites

What does nanotechnology integrate?

medicine & engineering to help quickly advance medicine

At what level does nanotechnology manipulate matter for new creation?

atomic & molecular scale

What is nanoscience?

the study of objects measured in nanometers

What is a nanometer?

1 billionth of a meter; 10^-9

How long is a helical turn of DNA?

3.4 nm

How long is the radius of a polymer molecule?

~10 nm

How big is a bacterial cell?

~2 micrometers

What are the advantages of nanomedicine?

-protect drugs from being degraded before reaching target -enhances drug absorption into tumors -allows better timing & distribution of drug -prevent drugs from interacting with normal cells, thus prevents side effects

Why is nanotech good for drug delivery to tumors?

The drug will travel and have large accumulation in tumors while minimal accumulation in normal cells/organs

What are the disadvantages to using nanotech?

-it is expensive -drug leakage -endocytosis of DS -vesicle size is small -reproducibility -stability

What is the range of the nanoscale DDS?

polymer-drug conjugate (1-10 nm) to organic/inorganic colloid (20-200 nm)

What is a liposome?

a self-closing spherical particle composed of natural or synthetic amphiphilic lipid molecules; hydrophilic head & hydrophobic tails

Why do liposomes help drugs become more biocompatible?

made of hydrophobic and hydrophilic layers that encapsulate the drug & protects from inactivating effects from the environemnt

What is the key benefit of liposomes for drugs?

change absorbance & biodistribution of the drug

What type of drug delivery are liposomes typically for?

intracellular delivery

What is an example of a liposome drug?

Doxil®-doxorubicin, a chemotherapy agent

Why is STEALTH® used with Doxil®?

allows drug to evade detection & destruction of the immune system

What are some other liposome drugs?

-AmBisome® (antifungal) -DepoCyt® -Marqibo® -Abraxane®

What are disease state are liposome/nanotech drugs usually designed for?

Cancer

What does the "clever/smart" drug targeting system coordinate?

-targeting moiety -the carrier -therapeutic drug

What are targeting moieties of smart liposome DDS?

-antibodies -proteins -lipoproteins -hormones -charged molecules -polysaccharides -low molecular weight ligands

What are the polymer forms of liposomes?

-polymeric strand -polymer-protein conjugate/complex -polyplex (polymer-DNA complex) -polymer-drug conjugate (with a linker between) -polymeric micelle (very complex)

What are nanoparticles comprised of?

polymers