NANOTECHNOLOGIES: THE NEW GENERATION OF MEDICINE Dr Mariano Licciardi

NANOTECHNOLOGIES › NANOMEDICINE = NANOPHARMACEUTICALS NANOPHARMACEUTICALS represent an emerging field where the nanoscale element may refer to either the size of the drug particle or to a therapeutic delivery system. These therapeutic systems may be defined as a complex system consisting of at least two components, one of which is the active ingredient. In this field the concept of nanoscale is the range from 1 to 500 nm.

NANOPHARMACEUTICALS have the finality to optimize drug delivery, bioavailability and in general increase the efficacy of already known drug molecules respect traditional dosage forms increase the efficacy of already known drug molecules respect traditional dosage forms in terms of: - chemical stability, - promote selective drug accumulation into the target organs or cells, - decrease administered dose, - decrease side and toxic effects, - allow administration through all administration routes.

Our research is focused on the preparation and characterization of bicompatible polymers useful to prepare nanopharmaceutical devices for pharmaceutical and biomedical applications. In particular our interest is addressed to some synthetic polyaminoacids, such as  -poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) and  - polyaspartylhydrazide (PAHy). Both polymers have attracted great interest, since they are highly water soluble, non toxic, non antigenic, non teratogenic and easily produced in large quantities and at low cost. In particular, the biocompatible polymers that we have investigated, have been used as starting materials to prepare: - macromolecular prodrugs, - polymeric micelles, - polymer-protein complexes, - polycations for gene therapy - nanoparticles

 -poly (N-2-hydroxyethylaspartamide) (PHEA)  -polyasparthylhydrazide (PAHy)

Drug Spacer Targeting group (Active Targeting) Polymeric Backbone (carrier) In macromolecular conjugates, active agents are covalently linked to hydrophilic polymeric carrier by hydrolizable bonds or spacers, so that the hydrolysis of active agent/polymer linkage is necessary to its release and to obtain the effect. The main advantage of these systems is constituted by their ability to efficiently protect linked drug molecules, to increase water-solubility, to increase bioavailabity and modulate drug targeting and biodistribution. 1 nm ‹ d ‹ 20 nm 1 nm ‹ d ‹ 20 nm

Alclofenac, Naproxen,Ketoprofen Ibuprofen, Diflunisal, Indometacin, Biphenilacetic acid Amantadine, Aciclovir, Ganciclovir, Zidovudine Citarabine Taxol Gemcitabine Examples of drugs linked to our polymers

RESULTS Increase water solubility and chemical stability of Taxol PHEA-2’-SUCCINYLTAXOL CONJUGATE Promote passive targeting to a specific organ: liver Eur. J. Pharm. Biopharm. 58, 151 (2004)

RESULTS Promote selective drug targeting (mediated by oxytocin receptors) inside ovarian and breast tumors Promote selective drug targeting (mediated by oxytocin receptors) inside ovarian and breast tumors PEG TAXOL OXYTOC IN Eur. J. Pharm. Biopharm. 66 (2007) 182

POLYMERIC MICELLES Polymeric micelles are colloidal systems obtained by self-assembling of amphiphilic copolymers above critical aggregation concentration (CAC). In the polymeric micelle the drug can be incorporated by physical or upon chemical linking to polymeric surfactant. The ability of polymeric micelles to promote drug absorption is correlated to the increase of cell membrane crossing, thus strongly improving drug bioavailability. 10 nm ‹ d ‹ 200 nm 10 nm ‹ d ‹ 200 nm

PHEA-PEG-C16 PAHy-PEG-C16

TUMOR DISTRIBUTION PROFILE J. Control. Release, 89, 285 (2003) PHEA-PEG-C16 micelles: slow and progressive tumor accumilation after parenteral administration in rat. in rat.

Macromol. Biosci. 4, (2004) 1028 INCREASED TAMOXIFEN SOLUBILITY AND CELL UPTAKE

Polymer-protein complexes Polymeric complexes are nanodevices formed by synthetic copolymers properly designed in order to complex small molecules or macromolecules by physical interactions. Colloidal resulting systems are able to strongly stabilize and protect peptide and protein molecules, allowing their administration for different administration routes. 10 nm ‹ d ‹ 250 nm 10 nm ‹ d ‹ 250 nm Application fields include successful oral delivery of peptides, proteins and vaccines.

RESULTS AFTER ORAL ADMINISTRATION OF INSULIN COMPLEXES International Application n. PCT/IT/2008/ Patent N. RM2007A GOLD MEDAL AT SALON INTERNATIONAL DES INVENTIONS GENEVE 2008 Insulin-polymer complex

INTERPOLYECTROLITE COMPLEXES Polyplexes (InterPolyElectrolyte Complexes, IPECs) are obtained by electrostatic interaction between cationic polymers (positively charged) and genetic material (such as plasmids or nucleic acid based drugs, negatively charged); these systems are able to condense genetic material (until to colloidal size), in order to make possible its introduction into cells and besides they protect DNA from nuclease degradation improving transfection efficiency. 50 nm ‹ d ‹ 500 nm 50 nm ‹ d ‹ 500 nm

RESULTS PHEA and PAHy cationic copolymers have been showed to be non toxic and able to transfect plasmid to cells in vitro J. Control. Release 131 (2008) 54 Nanomedicine 4(2) (2009) 291 Nanomedicine 5(2) (2010) 243

Nanoparticles Polymeric nanoparticles are drug loaded nanomatrices obtained by chemical or physical crosslinking of properly derivatized synthetic (PHEA, PAHy) or natural (polysaccarides) polymers. Nanoparticles can incorporate high amount of active molecules (high drug loading capacity) and control drug release rate and biodistribution. 10 nm ‹ d ‹ 500 nm 10 nm ‹ d ‹ 500 nm

PREPARATION OF POLYMERIC NANOPARTICLES BASED ON PHEA COPOLYMERS RESULTS: Stealth nanoparticles based on PHEA copolymers allowed successfully to escape reticulo-endotelial system reducing non productive effects and immunitary response. Biomacromolecules 7 (2006) 3083 macrophages PEG shell

CONCLUSIONS Nanotechnologies represent today a very promising approach to design and obtain drug and gene delivery systems with the aim to solve the problems connected with the traditional dosage forms. In the Laboratory of Biocompatible Polymers of the University of Palermo different nanotechnologies have been produced for drug and gene delivery; These nanotechnologies have been successfully proposed in nanomedicine, diagnostics and cosmetics. We hope that research in this field could go on obtaining more and more promising results. promising results.