ABSTRACT
A micelle consists of a corona formed by the hydrophilic blocks extending into the aqueous solution and a core formed by the hydrophobic segments. In order to achieve biocompatibility and ability to evade host defense mechanisms, the hydrophilic block is generally a derivative of polyethylene glycol (PEG). The composition of the hydrophobic block varies enormously, which can be tailored to encapsulate drug molecules with a variety of structures, lipophilicity, and charges, contributing to the versatility of polymeric micelles as drug carriers [1-8]. 35.2 Nanoviricides Polymeric Micelle
TechnologyNanoViricides, Inc., exploits its family of patented and proprietary polymeric micelle structures to develop its unique nanomedicines. This uniform (not random) polymer is made of a monomer that is composed of (a) an amphiphilic PEG chain, and (b) a multi-functional connector. The connector has covalently attached multiple lipid chains per monomer, thus resembling a biological lipid. In addition, the connector has multiple functional groups that enable attachment of specific targeting moieties that facilitate receptor-based interaction with a cell, virus, bacterium, or another assembly. Multiple chains come together to form micelles of 15-20 nm and larger sizes. These micelles enable the encapsulation of lipidic, amphiphilic, and aromatic guest molecules. These micelles exhibit the receptor ligand interactions, thus resembling microsomes or biological structures. Upon binding to its target via multipoint interactions, the micelle is capable of lipid-lipid fusion with the biological membrane of the target and thereby enables the transport of the encapsulated cargo, if present, into the target cell, virus particle, or bacterium. Immediately upon injection into the bloodstream, the solution undergoes infinite dilution, and yet the assembly remains intact because even the smallest structure remains micellar with this unique polymeric micelle chemistry. This is unlike liposomes, which fall apart upon injection, resulting in injection site reactions as well as significant “dumping” of the payload active pharmaceutical ingredient (API) long before reaching its target. This is described graphically in Figs. 35.1 and 35.2.
