Nanomaterials in Drug Delivery

Antonio Di Martino

dimartino@ft.utb.cz

What are nanomaterials?Materials of which at least one dimension is sized between 1-100 nm

Properties of nanomaterials differ significantly from other materials due to

surface area quantum effect

Applications

Cosmetics Pharmaceutics Medicine Electronics Construction Agriculture Energy

Why nanomaterials in drug delivery ?

High surface area bind adsorb carry

Size smaller than cells reach difficult access compartments

High permeability and retention effect (EPR)

administration of genes, proteins target the RE cells passive targeting

wide range of molecules

Nanoscale drug delivery systems

Nanoparticles

Nanoliposomes Dendrimers Polymerics Nanoshells

Fullerenes Nanotubes Nanopores Quantum Dots

Application of nanoscale delivery systems

Liposomes Consist of an aqueous core surrounded by a lipid bilayer

New generation liposomes can also be formed from polymers ( polymersomes)

Ability to encapsulate both hydrophilic and hydrophobic molecules

Benefits and limitations depend on physical and colloidal characteristics

phosphatdyl-ethanolamine

phosphatdyl-serine

phosphatdyl-choline

core

cholesterol

sphingomyelin

How to prepare liposomes? Different preparation methods

Mechanical agitation

Solvent evaporation

Solvent injection

Solubilization method

Parameters to consider during the preparation method selection

Characteristics of the material to be entrapped Dispersion medium Concentration of the encapsulated material Optimum size Polydispersivity Shelf-life

Drug loading

Hydrophobic molecules

Remain in the liposome bilayer High encapsulation efficiency

Hydrophilic molecules

Entrapped in the core Low encapsulation efficiency difficult to diffuse in and out Influence of pH

DoxorubicinPaclitaxel Prednisolone

Clinical applications Drug / protein delivery vehicles

Controlled and sustained release in situ Enhanced drug solubilization Enzyme replacement therapy Altered pharmacokinetics and bio-distribution

Antimicrobial, antiviral and antifungal therapy

Cancer therapy Carrier of small cytotoxic molecules Vehicle for macromolecules as cytokines and genes

Stability in physiological fluids represents the main problem!!!!!

NEW liposomes generation

Conclusions

Development of nano-carriers is bringing lots of hope and enthusiasm in the drug delivery research

Improve therapeutic efficiency

Enhance selectivity

Reduction of side effects

Ameliorate the patients quality of life