PHEA-graft-polybutylmethacrylate copolymer microparticles for delivery of hydrophobic drugs

Design of New Polyaspartamide Copolymers for siRNA Delivery in Antiasthmatic Therapy

Here, a novel protonable copolymer was realized for the production of polyplexes with a siRNA (inhibitor of STAT6 expression in asthma), with the aim of a pulmonary administration. The polycation was synthesized by derivatization of α,β-poly(N-2-hydroxyethyl)d,l-aspartamide (PHEA) with 1,2-Bis(3-aminopropylamino)ethane (bAPAE) in proper conditions to obtain a PHEA-g-bAPAE graft copolymer with a derivatization degree in amine (DDbAPAE%) equal to 35 mol%. The copolymer showed a proper buffering behavior, i.e., ranging between pH 5 and 7.4, to potentially give the endosomal escape of the obtained polycations. In effect, an in vitro experiment demonstrated the effect on biological membranes of the copolymer on bronchial epithelial cells (16-HBE) strongly dependent on the pH of the medium, i.e., higher at pH 5. bAPAE-based copolymers were further obtained with an increasing pegylation degree, i.e., equal to 1.9, 2.7, and 4.4 mol%, respectively. All the obtained copolymers were able to complex siRNA at a N/P ratio that decreases as the pegylation degree increases. At the same time, the tendency of polyplexes to aggregate and the capability to interact with mucin also decreases as the pegylation in the copolymer increases. Gene silencing experiments on 16-HBE showed that these copolymers have a significant role in improving the intracellular transport of naked siRNA, where the presence of PEG does not seem to hinder the cellular uptake of polyplexes. The latter obtained at polymer/siRNA weight ratio (R) equal to 10 with PHEA-g-PEG(C)-g-bAPAE also seems to be not susceptible to the presence of mucin, avoiding the polyanionic exchange of complexed siRNA, thus showing adequate behavior to be used as an effective vector for siRNA.

Physicochemical Properties of A New PEGylated Polybenzofulvene Brush for Drug Encapsulation

A new polymer brush was synthesized by spontaneous polymerization of benzofulvene macromonomer 6-MOEG-9-T-BF3k bearing a nona(ethylene glycol) side chain linked to the 3-phenylindene scaffold by means of a triazole heterocycle. The polymer structure was studied by SEC-MALS, NMR spectroscopy, and MALDI-TOF MS techniques, and the results supported the role of oligomeric initiatory species in the spontaneous polymerization of polybenzofulvene derivatives. The aggregation features of high molecular weight poly-6-MOEG-9-T-BF3k-FE were investigated by pyrene fluorescence analysis, dynamic light scattering studies, and transmission electron microscopy, which suggested a tendency towards the formation of spherical objects showing dimensions in the range of 20-200 nm. Moreover, poly-6-MOEG-9-T-BF3k-FE showed an interesting cytocompatibility in the whole concentration range tested that, besides its aggregation features, makes this polybenzofulvene brush a good polymer candidate for nanoencapsulation and delivery of drug molecules. Finally, the photo-physical features of poly-6-MOEG-9-T-BF3k-FE could allow the biodistribution of the resulting drug delivery systems to be monitored by fluorescence microscopy techniques.

Nanometric ion pair complexes of tobramycin forming microparticles for the treatment of Pseudomonas aeruginosa infections in cystic fibrosis

Sustained pulmonary delivery of tobramycin from microparticles composed of drug/polymer nanocomplexes offers several advantages against traditional delivery methods. Namely, in patients with cystic fibrosis, microparticle delivery can protect the tobramycin being delivered from strong mucoadhesive interactions, thus avoiding effects on its diffusion toward the infection site. Polymeric ion-pair complexes were obtained starting from two synthetic polyanions, through impregnation of their solid dissociated forms with tobramycin in aqueous solution. The structure of these polymeric systems was characterized, and their activities were examined against various biofilm-forming Pseudomonas aeruginosa. Once dried, the nanocomplexes can change their aggregation state, to form microparticle-based aggregates with a spherical shape and a micrometer size. In aqueous dispersions, the ion-pair complexes produced had nanometric size, negative ζ potential, and high biocompatibility toward human bronchial epithelium cells. The antibiofilm activity of these formulations was more efficient than for free tobramycin, with the antibiofilm activity against P. aeruginosa mucoid and nonmucoid end-stage strains isolated from cystic fibrosis lungs being of particular relevance.

Drug-Lipid-Surfactant Miscibility for the Development of Solid Lipid Nanoparticles

This research aimed to study the correlation between miscibility of flutamide (FLT), lipids and surfactant on the particle size of solid lipid nanoparticles (SLNs). Physical mixtures (PMs) of lipids-glyceryl monooleate (GMO), Precirol® (glyceryl palmitostearate, PRE), glyceryl monostearate (GMS), and Compritol® (glyceryl dibehenate, COM) were prepared with surfactant-Gelucire® (stearoyl polyoxyl-32 glycerides, GEL) 50/13 and 44/14. PMs were prepared in 5:2 w/w ratio (lipid:surfactant) and 2:1 w/w (Flutamide (FLT):lipids/GEL 50/13) by co-melting. Miscibility of PMs was investigated using modulated differential scanning calorimetry (MDSC). SLNs with and without drug were prepared using GEL 50/13 by the ultra-sonication method and particle size analysis was conducted. PMs of GMO, GMS, and PRE with both surfactants showed a decrease in the melting temperature, no change in melting and crystallization peak was observed with COM-GELs, indicating immiscibility. Similarly, MDSC data suggests good miscibility of FLT in GMO, GMS, and GEL 50/13 but not in PRE and COM. The particle size of drug-loaded SLNs prepared from GMO and GMS with GEL 50/13 was found to be 70.2 ± 5.4 and 92.6 ± 8.5 compared to > 200-nm particles obtained from PRE and COM. On lyophilization, an increase in particles size was observed with COM only. The particle size of SLNs with PRE and COM was prominently increased during stability studies indicating SLNs prepared with GMO and GMS are more stable due to miscibility and ability to reduce the crystallinity of FLT. The results established a good correlation between drug, lipids, and surfactants miscibility to the obtained particle size of SLNs before and after lyophilization. Graphical Abstract ᅟ.

Mucoadhesive solid lipid microparticles for controlled release of a corticosteroid in the chronic obstructive pulmonary disease treatment

Aim: Therapeutic efficacy of pulmonary diseases is often limited and drug delivery systems offer new solutions to clinical problems. Solid lipid microparticles (SLMs) are suggested as systems for the delivery of therapeutics to the lung as, because of their size, they are able to deposit into secondary bronchi. Materials & methods: Here, we describe two novel different SLMs using chitosan and alginate such as mucoadhesive polymers and we also studied their biocompatibility and their effectiveness compared with the free drug in controlling senescence and inflammatory processes in cigarette smoke extracts. Results: Data reported show that fluticasone propionate (FP)-loaded SLMs are more effective than FP alone in controlling oxidative stress. Conclusion: The therapeutic approach using FP-loaded microparticles could be a promising strategy for the treatment of the chronic inflammatory pulmonary diseases.

Nanoparticles of a polyaspartamide-based brush copolymer for modified release of sorafenib: In vitro and in vivo evaluation

In this paper, we describe the preparation of polymeric nanoparticles (NPs) loaded with sorafenib for the treatment of hepatocellular carcinoma (HCC). A synthetic brush copolymer, named PHEA-BIB-ButMA (PBB), was synthesized by Atom Trasnfer Radical Polymerization (ATRP) starting from the α-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) and poly butyl methacrylate (ButMA). Empty and sorafenib loaded PBB NPs were, then, produced by using a dialysis method and showed spherical morphology, colloidal size, negative ζ potential and the ability to allow a sustained sorafenib release in physiological environment. Sorafenib loaded PBB NPs were tested in vitro on HCC cells in order to evaluate their cytocompatibility and anticancer efficacy if compared to free drug. Furthermore, the enhanced anticancer effect of sorafenib loaded PBB NPs was demonstrated in vivo by using a xenograft model, by first allowing Hep3B cells to grow subcutaneously into nude mice and then administering sorafenib as free drug or incorporated into NPs via intraperitoneal injection. Finally, in vivo biodistribution studies were performed, showing the ability of the produced drug delivery system to accumulate in a significant manner in the solid tumor by passive targeting, thanks to the enhanced permeability and retention effect.

Polyaspartamide-Based Nanoparticles Loaded with Fluticasone Propionate and the In Vitro Evaluation towards Cigarette Smoke Effects

This paper describes the evaluation of polymeric nanoparticles (NPs) as a potential carrier for lung administration of fluticasone propionate (FP). The chosen polymeric material to produce NPs was a copolymer based on α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) whose backbone was derivatised with different molecules, such as poly(lactic acid) (PLA) and polyethylenglycol (PEG). The chosen method to produce NPs from PHEA-PLA-PEG₂₀₀₀ was the method based on high-pressure homogenization and subsequent solvent evaporation by adding Pluronic F68 during the process and trehalose before lyophilisation. Obtained colloidal FP-loaded NPs showed a slightly negative surface charge and nanometric dimensions that are maintained after storage for one year at −20 °C and 5 °C. The FP loading was about 2.9 wt % and the drug was slowly released in simulated lung fluid. Moreover, the obtained NPs, containing the drug or not, were biocompatible and did not induce cell necrosis and cell apoptosis on bronchial epithelial cells (16-HBE). Further in vitro testing on cigarette smoke extract (CSE)-stimulated 16-HBE revealed that FP-loaded NPs were able to reduce the survivin expression, while either free FP or empty NPs were not able to significantly reduce this effect.

Cell Permeating Nano-Complexes of Amphiphilic Polyelectrolytes Enhance Solubility, Stability, and Anti-Cancer Efficacy of Curcumin

Many hydrophobic drugs encounter severe bioavailability issues owing to their low aqueous solubility and limited cellular uptake. We have designed a series of amphiphilic polyaspartamide polyelectrolytes (PEs) that solubilize such hydrophobic drugs in aqueous medium and enhance their cellular uptake. These PEs were synthesized through controlled (∼20 mol %) derivatization of polysuccinimide (PSI) precursor polymer with hydrophobic amines (of varying alkyl chain lengths, viz. hexyl, octyl, dodecyl, and oleyl), while the remaining succinimide residues of PSI were opened using a protonable and hydrophilic amine, 2-(2-amino-ethyl amino) ethanol (AE). Curcumin (Cur) was employed as a representative hydrophobic drug to explore the drug-delivery potential of the resulting PEs. Unprecedented enhancement in the aqueous solubility of Cur was achieved by employing these PEs through a rather simple protocol. In the case of PEs containing oleyl/dodecyl residues, up to >65000× increment in the solubility of Cur in aqueous medium could be achieved without requiring any organic solvent at all. The resulting suspensions were physically and chemically stable for at least 2 weeks. Stable nanosized polyelectrolyte complexes (PECs) with average hydrodynamic diameters (DH) of 150-170 nm (without Cur) and 220-270 nm (after Cur loading) were obtained by using submolar sodium polyaspartate (SPA) counter polyelectrolyte. The zeta potential of these PECs ranged from +36 to +43 mV. The PEC-formation significantly improved the cytocompatibility of the PEs while affording reconstitutable nanoformulations having up to 40 wt % drug-loading. The Cur-loaded PECs were readily internalized by mammalian cells (HEK-293T, MDA-MB-231, and U2OS), majorly through clathrin-mediated endocytosis (CME). Cellular uptake of Cur was directly correlated with the length of the alkyl chain present in the PECs. Further, the PECs significantly improved nuclear transport of Cur in cancer cells, resulting in their death by apoptosis. Noncancerous cells were completely unaffected under this treatment.

Pegylated Polyaspartamide-Polylactide-Based Nanoparticles Penetrating Cystic Fibrosis Artificial Mucus

Here, the preparation of mucus-penetrating nanoparticles for pulmonary administration of ibuprofen in patients with cystic fibrosis is described. A fluorescent derivative of α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide is synthesized by derivatization with rhodamine, polylactide, and poly(ethylene glycol), to obtain polyaspartamide-polylactide derivatives with different degrees of pegylation. Starting from these copolymers, fluorescent nanoparticles with different poly(ethylene glycol) content, empty and loaded with ibuprofen, showed spherical shape, colloidal size, slightly negative ζ potential, and biocompatibility toward human bronchial epithelial cells. The high surface poly(ethylene glycol) density of fluorescent nanoparticles and poly(ethylene glycol) brush-like conformation assumed on their surface, conferred to pegylated nanoparticles the mucus-penetrating properties, properly demonstrated by assessing their ability to avoid interactions with mucus components and to penetrate cystic fibrosis artificial mucus. Finally, ibuprofen release profile and uptake capacity within human bronchial epithelial cells in the presence of cystic fibrosis artificial mucus showed how these mucus-penetrating nanoparticles could rapidly diffuse through the mucus barrier reaching the mucosal surface, where they could offer a sustained delivery of ibuprofen at the site of disease.

Inulin-Ethylenediamine Coated SPIONs Magnetoplexes: A Promising Tool for Improving siRNA Delivery

PURPOSE

An inulin based polycation (Inu-EDA) has been synthesized by the grafting of ethylenediamine molecules onto inulin backbone. The obtained inulin copolymer has been though to coat SPIONs (IC-SPIONs) and obtain stable magnetoplexes by complexation of IC-SPIONs with a model duplexed siRNA, for improving oligonucleotide transfection efficiency.

METHODS

The physical-chemical characteristics of IC-SPIONs and IC-SPIONs/siRNA magnetoplexes have been investigated by scanning and transmission electron microscopies, dynamic light scattering, FT-IR and qualitative surface elementary analysis. Cell compatibility and internalization in vitro of IC-SPIONs have been evaluated by MTS and fluorescence microscopy respectively on cancer (HCT116) and normal human (16HBE) cells. The efficiency of gene silencing effect of magnetoplexes was studied on both tumoral (JHH6) and non tumoral (16HBE) cell lines also by applying an external magnet.

RESULTS

IC-SPIONs showed dimension of 30 nm and resulted cytocompatible on the tested cell lines; in the presence of an external magnet, the magnetic force enhanced the IC-SPIONs uptake inside cells. Magnetically improved transfection was observed in 16HBE cells under magnetofective conditions, in accordance with the IC-SPIONs uptake enhancement in the presence of an external magnet.

CONCLUSIONS

These findings support the potential application of this system as a magnetically targeted drug delivery system. Graphical Abstract Magnetically improved siRNA transfection in cells under magnetofective conditions upon uptake enhancement of IC-SPIONs in the presence of an external magnet.

Polyaspartamide-Polylactide Graft Copolymers with Tunable Properties for the Realization of Fluorescent Nanoparticles for Imaging

Here, the synthesis and the characterization of novel amphiphilic graft copolymers with tunable properties, useful in obtaining polymeric fluorescent nanoparticles for application in imaging, are described. These copolymers are obtained by chemical conjugation of rhodamine B (RhB) moieties, polylactic acid (PLA), and O-(2-aminoethyl)-O'-methyl poly(ethylene glycol) (PEG) on α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA). In particular, PHEA is first functionalized with RhB to obtain PHEA-RhB with a derivatization degree in RhB (DDRhB ) equal to 0.55 mol%. By varying the reaction conditions, different amounts of PLA are grafted on PHEA-RhB to obtain PHEA-RhB-PLA with DDPLA equal to 1.9, 4.0, and 6.2 mol%. Then, PEG chains are grafted on PHEA-RhB-PLA derivatives to obtain PHEA-RhB-PLA-PEG graft copolymers. The preparation of polymeric fluorescent nanoparticles with tunable properties and spherical shape is described by using PHEA-RhB-PLA-PEG with DD in PLA and PEG equal to 4.0 and 4.9 mol%, by following easily scaling up processes, such as emulsion-solvent evaporation and high pressure homogenization (HPH)-solvent evaporation techniques.

Polybenzofulvene derivatives bearing dynamic binding sites as potential anticancer drug delivery systems

A polybenzofulvene brush is functionalized with a synthetic receptor capable of interacting with doxorubicin.

Amphiphilic inulin graft co-polymers as self-assembling micelles for doxorubicin delivery

This paper reports the synthesis and characterization of a new amphiphilic inulin graft copolymer able to self-assemble in water into a micelle type structure and to deliver the anticancer model drug doxorubicin. For this aim, inulin was chemically modified in the side chain with primary amine groups (INU-EDA) and these were used as reactive moieties for the conjugation of poly ethylene glycol 2000 and succinyl-ceramide. The CMC of obtained amphiphilic inulin derivatives (INU-ceramide and INU-ceramide-PEG₂₀₀₀) was measured by means of fluorescence analysis using pyrene as the fluorescent probe. The obtained micelles were characterized by DLS and AFM analysis and the ability to release the loaded doxorubicin was studied in different media. Finally the cytotoxicity profile on both cancer (HCT116) and normal (16 HBE) cell lines and in vitro ability to deliver the drug into cancer cells were evaluated.

Polymeric nanocarriers for magnetic targeted drug delivery: preparation, characterization, and in vitro and in vivo evaluation

In this paper the preparation of magnetic nanocarriers (MNCs), containing superparamagnetic domains, is reported, useful as potential magnetically targeted drug delivery systems. The preparation of MNCs was performed by using the PHEA-IB-p(BMA) graft copolymer as coating material through the homogenization-solvent evaporation method. Magnetic and nonmagnetic nanocarriers containing flutamide (FLU-MNCs) were prepared. The prepared nanocarriers have been exhaustively characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and magnetic measurements. Biological evaluation was performed by in vitro cytotoxicity and cell uptake tests and in vivo biodistribution studies. Magnetic nanocarriers showed dimensions of about 300 nm with a narrow size distribution, an amount of loaded FLU of 20% (w/w), and a superparamagnetic behavior. Cell culture experiments performed on prostate cancer cell line LNCaP demonstrated the cytotoxic effect of FLU-MNCs. In vivo biodistribution studies carried out by the application of an external magnetic field in rats demonstrated the effect of the external magnet on modifying the biodistribution of FLU-MNCs. FLU-MNCs resulted efficiently internalized by tumor cells and susceptible to magnetic targeting by application of an external magnetic field. The proposed nanocarriers can represent a very promising approach to obtain an efficient magnetically targeted anticancer drug delivery system.

Emerging applications of nanoparticles for lung cancer diagnosis and therapy

Lung cancer is by far the leading cause of cancer-related mortality worldwide, most of them being active tobacco smokers. Non small cell lung cancer accounts for around 85% to 90% of deaths, whereas the rest is contributed by small cell lung cancer. The extreme lethality of lung cancer arises due to lack of suitable diagnostic procedures for early detection of lung cancer and ineffective conventional therapeutic strategies. In course with desperate attempts to address these issues independently, a multifunctional nanotherapeutic or diagnostic system is being sought as a favorable solution. The manifestation of physiochemical properties of such nanoscale systems is tuned favorably to come up with a versatile cancer cell targeted diagnostic and therapeutic system. Apart from this, the aspect of being at nanoscale by itself confers the system with an advantage of passive accumulation at the site of tumor. This review provides a broad perspective of three major subclasses of such nanoscale therapeutic and diagnostic systems which include polymeric nanoparticles-based approaches, metal nanoparticles-based approaches, and bio-nanoparticles-based approaches. This review work also serves the purpose of gaining an insight into the pros and cons of each of these approaches with a prospective improvement in lung cancer therapeutics and diagnostics.