12 - Polysaccharide nanomicelles as drug carriers

Abstract

The unique self-assembling ability with the capacity to load hydrophobic and hydrophilic molecules makes polymeric micelles a promising delivery system among other nanocarriers in drug delivery and targeting. Amphiphilic block copolymers self-assemble in aqueous media to produce micelles in nanosize range (10–100 nm). Polymeric micelles are capable of solubilizing poorly soluble drugs, and can control or modify the drug release with an ability to release the drugs at specific target site in response to respective external stimuli at the desired site. To date, many polymeric micelles were developed using synthetic amphiphilic block polymers and copolymers of which, few are in clinical stage. The major apprehensions with these synthetic products are biocompatibility, immunogenicity low cellular uptake, short half-life, and toxicity. Natural polysaccharides demonstrate potential in drug delivery due to their hydrophilicity, biodegradability, biocompatibility, and flexibility to undergo modification. Modification of polysaccharide backbone with hydrophobic moiety increases self-assembling ability, making them more suitable to produce colloidal nanocarriers such as micelles. Polysaccharide-based micelle systems also have the advantage of attaining increased oral or topical absorption and enhanced tumor penetration due to mucoadhesive nature of few polysaccharides like cellulose and chitosan. The present chapter will discuss different polysaccharide materials used to produce nanomicelles and their structural modifications. Formulation optimization, characterization techniques, and different evaluation methods along with application of nanomicelles through various routes of administration in drug delivery will be elaborated with special emphasis on cancer targeting, oral, topical, and ophthalmic delivery. The chapter will also focus on the current technologies in development, clinical stage, marketed products if any, and patents.