Polymeric Micelles Dr. Aws Alshamsan Department of Pharmaceutics Office: AA87 Tel:

Definition Nano-sized particles that are made up of polymer chains and are usually spontaneously formed by self-assembly in a liquid.

Polymeric Micelles Amphiphilic polymer chains that self- assemble into nano-sized spherical structures in aqueous medium

Polymers Polymers refer to large molecules whose structure depends on the monomer or monomers used in their preparation

Copolymers

Structure Micelles have a core-shell structure. The core of the micelles contains drugs, while the shell provides interactions with the solvent to stabilize the micelles.

nm self-assembly hydrophobic block hydrophilic block diblock copolymers in selective solvent hydrophobic drug Polymeric micelles polymeric micelle in water 7

Methods commonly used for physical drug encapsulation in polymeric micelles: A) dialysis method; B) oil/water emulsion method; C) solvent evaporation method; D) Co-solvent evaporation method.

Thermodynamic stability Compared to surfactant micelles, polymeric micelles are generally more stable, with a remarkably lowered CMC, and have a slower rate of dissociation.

Characterization Size distribution by DLS and visualization by TEM

Modes of drug release from polymeric micelles

Polymeric Micelles Advantages: ◦Biocompatibility ◦Biodegradability ◦Easy to prepare ◦Chemical modification is easy ◦Stealth property Disadvantages: ◦Highly unstable ◦Must be made fresh ◦Cannot be stored