Project: “SELF-ASSEMBLY POLYMERIC NANO-BIOMATERIALS FOR DRUG DELIVERY AND TARGETING” -“NANOTAR” (Marie Curie Reintegration-European Union’s – Seventh Framework Programme under grant agreement #612675-MC-NANOTAR)
Scientific background and Relevance
Approximately 35 million people are infected with HIV worldwide and 2.3 million in Europe. HIV is the leading cause of death due to infection and claims approximately 2-2.5 million lives every year. The High Activity Antiretroviral Therapy (HAART) is a combination of at least three antiretrovirals (ARVs) administered on a daily basis for life to control the infection. HAART made the disease manageable, extending the lifespan of the infected patients for more than one decade. Epidemiology reveals that optimal therapeutic results are attained only when treatment adherence levels are >95%.
The frequent administration of several drugs in high doses is a cause of patient incompliance and a source of resistance. Infected children constitute a high-risk sub-population due to the lack of approved drugs and appropriate pharmaceutical products. The World Health Assembly recognized children’s right to access safe, effective and proven medicines. HIV is chronic because intracellular and anatomical viral reservoirs perpetuate the infection.
Active transport mechanisms involving proteins of the ATP-binding cassette (ABCs) (e.g., P-glycoprotein, P-gp) in the intestinal epithelium remove ARVs in the basolateral-to-apical direction (against a concentration gradient), reducing their oral bioavailability. A remarkable technological gap between the commercially available products and the optimal features envisioned for a compliant ARV medication is apparent. Emerging research is increasingly being focused on the development of innovative ARV delivery strategies.
TB is the second most lethal infection behind HIV, accounting for 1.5 million annual deaths. The WHO declared the global sanitary emergency in 1993 owing to the high prevalence of the HIV/TB co-infection. The first-line pharmacotherapy of non-drug resistant TB is divided into two phases combining four drugs and lasting at least six months. Both phases comprise the co-administration of rifampicin (RIF) and isoniazid (INH).
Regular TB is curable but it still represents more than 25% and 2.4% of the preventable and of all deaths worldwide, respectively. The main reason of therapeutic failure is low patient compliance. As in HIV, the profitability of innovative products is low, accounting for the relatively slow pace in drug discovery and pharmaceutical development. New drugs are expected to be more effective against resistant strains than the first-line ones, though they are more expensive and less affordable in the countries mainly hit by the scourge.
The development of innovative pharmaceutical products of first-line drugs could lead to a breakthrough in the therapy. FP6 supported TB projects in vaccines, drugs and diagnostics, for a total budget of 60 million Euros. FP7 continues with this level of support. Similarly to HIV, nanotechnology research for TB treatment is not addressed in FP7.
Pharmaceutical Nano-Materials Science
Until the mid-1990s, the development of pharmaceutical and drug delivery products relied on a trial-and-error approach that resulted in inefficient, time-consuming and expensive development processes. Pharmaceutical Materials Science has emerged as a new discipline defined as the study of the physical properties and behavior of materials of pharmaceutical interest (MPIs) in relation to product performance; MPIs comprise drugs and non-pharmacologically active excipients.
The implementation of the basic principles of materials science catalyzed the transformation of pharmaceutical product development from an art to a science. The study of the relationship between the structure and the properties of drugs, excipients and their combinations has become a pillar of the rational development of innovative products. The consolidation of robust and versatile technology platforms is crucial to reduce the drug attrition rates.
Tailoring products with features required by children is another challenge. The global nanotechnology-based drug delivery market is expected to become a multibillion dollar market in 2015. Following this, the field could be renamed asPharmaceutical Nanomaterials Science.
Pharmaceutical innovation in HIV and TB. In clear contrast with cancer, pharmaceutical innovation in HIV/AIDS and TB is scarce. Regardless of the programs established by the WHO, the EC and U.S., only few countable research groups work at the interface of pharmaceutical nanomaterials scienceand these diseases worldwide. Thus, the foundation of disease-oriented research programs to provide a more timely response to these epidemics is called for. Considering the challenges in the therapy of HIV and TB, this project investigates the development of improved platforms for the administration of drugs to treat HIV/AIDS and TB.
Our contribution to innovation in the therapy of HIV
My research group has pioneered the study of innovative micro and nano-pharmaceutical products for the therapy of HIV with special focus on the pediatric population and employing different production processing methods (e.g., spray-drying) that are scalable under an industrial setting. We developed the first aqueous pediatric product of the first-line ARV efavirenz employing poly(ethylene oxide)-b-poly(propylene oxide) (PEO-PPOs) polymeric micelles as drug nanocarriers (Chiappetta et al., Nanomedicine (Lond.), 2010; Chiappetta et al., Biomaterials, 2011; Chiappetta et al., Curr HIV Res, 2011).
After a very comprehensive preclinical assessment that showed the significant increase of the oral bioavailabilty upon nano-encapsulation, we compared the performance of a nano-formulation produced with all US Food and Drug Administration (US-FDA)-approved components with that of a reference capsule in one adult healthy volunteer, where we confirmed the sharp increase of the oral bioavailability (Sosnik & Carcaboso, Adv Drug Deliv Rev, 2014). A clinical protocol already approved by the Argentine regulatory agency (ANMAT) will evaluate the pharmacokinetics of this novel product in 12 adult healthy volunteers (cross-over experimental design).
The central nervous system is one of the most challenging HIV reservoirs. The infection contributes to its progressive deterioration, a disease referred as HIV-associated neurocognitive disorder. We have targeted efavirenz to the brain by the intranasal route, increasing the relative exposure index with respect to plasma by up to 3-fold (Chiappetta et al., Nanomedicine (Lond.), 2013).
The investigation of production methods for scale-up of micro and nanomedicines under an industrial setting is another challenge to ensure clinical translation. We have investigated spray-drying and electrospraying for the encapsulation of hydrophilic and lipophilic ARVs (Tshweu et al., Nanomedicine (Lond.), 2014; Seremeta et al., Colloids Surf B, 2013 and 2015; Seremeta et al., J Mater Chem B, 2015).
These encapsulation approaches led to a significant increase of the oral bioavailabilty with respect to the free drugs. More recently, we reported on the first drug delivery system for the controlled release of an ARV by the oral route. To achieve this, an innovative simplified two-component nanoparticle-in-microparticle delivery system (NiMDS) comprised of pure nanoparticles of indinavir free base, a protease inhibitor used as model drug, were encapsulated within film-coated mucoadhesive microparticles and extensively characterized in vitro and in vivo (Imperiale et al., Biomaterials, 2015).
Aiming to increase the chances of bench-to-bedside translation, all the components used in this development are approved for pharmaceutical use by the US Food and Drug Administration and/or the European Medicines Agency. First, the drug particle size was reduced employing a bottom-up method, nanoprecipitation. In a complementary study, we also demonstrated the ability to conduct the nanonization stage by means of a Supercritical Anti-Solvent method (Imperiale et al., Drug Dev Ind Pharm, 2014). Then, the pure drug nanoparticles were encapsulated within chitosan/alginate polyelectrolyte microparticles that were film-coated with a series of biocompatible copolymers to increase their stability in the gastrointestinal tract.
The microencapsulation efficiency was almost 100% and the maximum cargo achieved approximately 43% w/w (based on dry weight). This outstanding achievement would allow the administration of high drug doses by adding reasonable amounts of non-pharmacologically active excipients. Finally, the NiMDSs were re-encapsulated in gastro-resistant capsules that withstood the gastric medium and disintegrated very fast in intestinal medium, releasing the drug-loaded microparticles that underwent mucoadhesion. After a very comprehensive characterization in vitro, we addressed the first preclinical phase that was a decisive stage to confirm the performance of this innovative drug delivery system.
In these studies, we compared the oral pharmacokinetics of NiMDSs with those of the pure unprocessed and nanonized drug in mongrel dogs. Results were very promising. Due to the increase of the surface area, nanonized IDV showed a significant 22-fold increase of the oral bioavailability with respect to the unprocessed drug. In addition, detectable levels in plasma until 24 h suggested the physical entrapment and retention of the nanoparticles in the intestinal mucosa. These results supported the beneficial contribution of the nanonization process.
Furthermore, encapsulation of the nanoparticles in mucoadhesive microparticles improved the biopharmaceutical performance of the drug even more, with a 47-fold bioavailability increase and a prolongation of the apparent half-life of 95 times, from 0.8 to 76 h. This platform is being transferred to gold-standard protease inhibitors.
Our contribution to innovation in the therapy of TB
The disadvantageous therapy conditions of the pediatric populations are a main concern. Aiming to improve the therapy of pediatric TB, we investigated the encapsulation of the first-line drug rifampicin within “flower-like” polymeric micelles (Moretton et al., Colloids Surf B, 2010; Moretton et al., J R Soc Interface, 2012). Encapsulation increased the aqueous solubility of the drug by 5.4 times and chemically stabilized it under extreme acid conditions in presence of soluble isoniazid, another first- line antituberculosis drug that is co-administered with rifampicin and that catalyzes its degradation in the stomach (Moretton et al., Nanomedicine (Lond.), 2014).
Nano-encapsulation increased rifampicin bioavailability up to 3.3 times. This formulation constitutes the first attempt to develop a liquid pediatric fixed dose combination of rifampicin/isoniazid. These micelles were also surface-modified with hydrolyzed galactomannan to actively target the drug to macrophages through lectin-like receptors (Moretton et al., J Biomed Nanotechnol, 2013); alveolar macrophages are the main reservoir of the Mycobatcerium tuberculosisthus we envision the use of the micelles by inhalation.
NANOTAR investigates different strategies to extend and improve the performance of the platform of POLYMERIC MICELLES to non-parenteral administration routes with special interest in the oral, ophthalmic and intranasal ones.
Glisoni RJ, Sosnik A, Novel poly(ethylene oxide)-co-poly(propylene oxide) copolymer-glucose conjugate by the microwave-assisted ring opening of a sugar lactone, Macromol Biosci 14, 1639-1651 (2014).
Sosnik A, Carcaboso A, Nanomedicines in the future of pediatric therapy, Adv Drug Deliv Rev 73, 140-161 (2014).
Sosnik A, das Neves J, Sarmento B, Mucoadhesive polymers in the design of nano-drug delivery systems for administration by non-parenteral routes: A review, Prog Polym Sci 39, 2030-2075 (2014).
Sosnik A, Do not forget the forgotten diseases…and patients, Invited conference at the Annual Meeting of the Israeli Chapter of the Controlled Release Society. Ma’alot, Israel 2014.
Sosnik A, Pediatric nanomedicine: Minimizing the size to maximize the benefit, Invited webinar at the Global Research in Pediatrics (GRiP) Network of Excellence “Meet the expert in pediatric formulation” webinar series, July 2014.
Sosnik A, Polymeric micelles for improving the oral bioavailability of drugs: From self-assembly to bench-to-bedside translation, Invited conference at the 2014 IUPAC World Polymer Congress-MACRO 2014. Chiang Mai, Thailand 2014.
Sosnik A, Finding the Balance between Innovation and Bench-to-bedside Translation in HIV Therapy, Invited conference at CLINAM 7/2014-The European Summit for Clinical Nanomedicine and Targeted Medicine, European Foundation for Clinical Nanomedicine. Basel, Switzerland 2014.
Glisoni R, Sosnik A, Microwave-assisted ring opening conjugation of a sugar lactone to polymeric micelles for active targeting drug delivery, IV Latin American School of Nanomedicine. Buenos Aires, Argentina 2014.
Quintana S, Glisoni RJ, Molina Soler MA, Moglioni A, Calderón M, Sosnik A, Chitosan-g-oligo(epsilon-caprolactone) polymeric micelles: Synthesis, physicochemical and cytocompatibility characterization and rifampicin encapsulation, 2014 IUPAC World Polymer Congress-MACRO 2014. Chiang Mai, Thailand 2014.
Sosnik A, Vázquez-González B, Imperiale JC, Muñoz-Muñoz F, Burillo G, Cedillo G, Bucio E, Muco-adhesive chitosan-g-poly(NIPAAm) polymeric micelles by gamma radiation: Synthesis and chemical and self-assembly characterization, 2014 IUPAC World Polymer Congress-MACRO 2014. Chiang Mai, Thailand 2014.