1. Active
targeted drug delivery most often occurs as a result of tight binding between
receptors present on the surface of a target cell and a targeting agent that is
often the actual naturally-occurring ligand (a molecule that binds to a
receptor) specific for the target receptor or has been designed to mimic ligand
binding effects. Active targeted drug
delivery can thus be defined as the delivery of a drug to a particular tissue
or cell type through specific and precise binding of the drug to the target
tissues or cells. Passive targeted drug
delivery is a mechanism and process by which certain sizes of molecules tend to
preferentially accumulate in tumor tissues and is also known as the enhanced
permeability retention (EPR) effect. It
is based upon the considerable blood supply requirements of tumors. As tumors grow and tumor cells divide new
vasculature is generated locally to support this growth. Newly formed blood vessels are usually
abnormal in form and architecture, with poor alignment of endothelial cells
resulting in wide fenestrations lacking a smooth muscle layer. In addition, lymphatic drainage is usually
hindered proximal to tumor tissues.
These factors all contribute to fluid transport dynamics that promote
the preferential uptake of macromolecules of a certain size by tumor tissues.
4. i) Drug incorporation and release; ii) Nanoparticle/drug complex formulation
stability and shelf-life; iii) Biocompatibility;
iv) Biodistribution and targeting
efficiency; v) Functionality
7. Polylactides
are biocompatible and can be custom synthesized to meet both size and
conformational requirements that allow for the encapsulation of a variety of
drugs. PLA degradation allows for drug
release and its rate can be controlled by the polymer's molecular weight,
conformation and overall composition.
10. For
the attachment of targeting moieties as well as side-chains to promote the
aqueous solubility of therapeutic agents.
13. By
Hirsh-Bingel chemistry (use of malonate derivatives to introduce side chains
onto fullerenes) and assessed their potential as gene delivery vehicles. Engel noted that most C60 derivatives
are only slightly soluble in an aqueous environment and the use of solvents in
their manufacture could contribute to observed cytotoxicity. The Hirsch-Bingel reaction is one of the
simplest and highest yielding C60 functionalization methods
known. It involves the attack of C60
by a nucleophilic anion followed by elimination of a negatively charged ion to
yield the final derivatized products which may be positively charged,
negatively charged or neutral, with charge considerably affecting water
solubility.
16. EE
= (The amount of 5FU in the nanoparticles/The total amount of 5fU) *100%
LC = (The amount of 5FU in the nanoparticles/The
total amount of nanoparticle wt) *100%
