Delia Mandracchia

Hyaluronic acid and its derivatives in drug delivery and imaging: Recent advances and challenges

Hyaluronic acid (HA) is a biodegradable, biocompatible, nontoxic, and non-immunogenic glycosaminoglycan used for various biomedical applications. The interaction of HA with the CD44 receptor, whose expression is elevated on the surface of many types of tumor cells, makes this polymer a promising candidate for intracellular delivery of imaging and anticancer agents exploiting a receptor-mediated active targeting strategy. Therefore, HA and its derivatives have been most investigated for the development of several carrier systems intended for cancer diagnosis and therapy. Nonetheless, different and important delivery applications of the polysaccharide have also been described, including gene and peptide/protein drugs delivery. The aim of this review was to provide an overview of the existing recent literature on the use of HA and its derivatives for drug delivery and imaging. Notable attention is given to nanotheranostic systems obtained after conjugation of HA to nanocarriers as quantum dots, carbon nanotubes and graphene. Meanwhile, attention is also paid to some challenging aspects that need to be addressed in order to allow translation of preclinical models based on HA and its derivatives for drug delivery and imaging purposes to clinical testing and further their development.

Paclitaxel-eluting biodegradable synthetic vascular prostheses: a step towards reduction of neointima formation?

Background— Clinical small-caliber vascular prostheses are unsatisfactory. Reasons for failure are early thrombosis and late intimal hyperplasia. We thus prepared biodegradable small-caliber vascular prostheses using electrospun polycaprolactone (PCL) with slow-releasing paclitaxel (PTX), an antiproliferative drug. Methods and Results— PCL solutions containing PTX were used to prepare nonwoven nanofibre-based 2-mm ID prostheses. Mechanical morphological properties and drug loading, distribution, and release were studied in vitro. Infrarenal abdominal aortic replacement was carried out with nondrug-loaded and drug-loaded prostheses in 18 rats and followed for 6 months. Patency, stenosis, tissue reaction, and drug effect on endothelialization, vascular remodeling, and neointima formation were studied in vivo. In vitro prostheses showed controlled morphology mimicking extracellular matrix with mechanical properties similar to those of native vessels. PTX-loaded grafts with suitable mechanical properties and controlled drug-release were obtained by factorial design. In vivo, both groups showed 100% patency, no stenosis, and no aneurysmal dilatation. Endothelial coverage and cell ingrowth were significantly reduced at 3 weeks and delayed at 12 and 24 weeks in PTX grafts, but as envisioned, neointima formation was significantly reduced in these grafts at 12 weeks and delayed at 6 months. Conclusions— Biodegradable, electrospun, nanofibre, polycaprolactone prostheses are promising because in vitro they maintain their mechanical properties (regardless of PTX loading), and in vivo show good patency, reendothelialize, and remodel with autologous cells. PTX loading delays endothelialization and cellular ingrowth. Conversely, it reduces neointima formation until the end point of our study and thus may be an interesting option for small caliber vascular grafts.

Amphiphilic inulin-d-α-tocopherol succinate (INVITE) bioconjugates for biomedical applications

Herein is reported the synthesis and characterization of innovative inulin (INU)-vitamin E succinate (VITE) bioconjugates (INVITE). The obtained amphiphilic INU-based polymers, self-assembling in nanostructures, have been thought as new drug delivery systems (DDS) for the therapy of urinary tract infections (UTI). The synthesis of INVITE bioconjugates was carried out in bulk, without isolation of intermediate products, to reduce the amount of solvents used in the purification steps and to prevent possible VITE oxidation during work up. Six different INVITE conjugates (INVITE 1-6) have been synthesized by varying both the relative amount of VITE with respect to INU repetitive units and the reaction temperature. Afterwards, the ability of the new conjugates to form micelle systems, by applying two different established methods for critical aggregation concentration (CAC) evaluation, has been verified. Both methods produced similar CAC values ranging from 2.5 × 10(-3)mM to 2.4 × 10(-2)mM in agreement with the different degrees of derivatization shown by the INVITE 1-6 conjugates. The mean diameter of prepared INVITE micelles, resulted in the range 24-60 nm. The size of the obtained INVITE micelles did not change as measured at different time points up to 12 days, so confirming their stability upon storage.

Intranasal delivery of dopamine to the striatum using glycol chitosan/sulfobutylether-β-cyclodextrin based nanoparticles.

The aim of this study was to evaluate chitosan (CS)-, glycol chitosan (GCS)- and corresponding thiomer-based nanoparticles (NPs) for delivering dopamine (DA) to the brain by nasal route. Thus, the polyanions tripolyphosphate and sulfobutylether-β-cyclodextrin (SBE-β-CD), respectively, were used as polycation crosslinking agents and SBE-β-CD also in order to enhance the DA stability. The most interesting formulation, containing GCS and SBE-β-CD, was denoted as DA GCS/DA-CD NPs. NMR spectroscopy demonstrated an inclusion complex formation between SBE-β-CD and DA. X-ray photoelectron spectroscopy analysis revealed the presence of DA on the external surface of NPs. DA GCS/DA-CD NPs showed cytotoxic effect toward Olfactory Ensheathing Cells only at higher dosage. Acute administration of DA GCS/DA-CD NPs into the right nostril of rats did not modify the levels of the neurotransmitter in both right and left striatum. Conversely, repeated intranasal administration of DA GCS/DA-CD NPs into the right nostril significantly increased DA in the ipsilateral striatum. Fluorescent microscopy of olfactory bulb after acute administration of DA fluorescent-labeled GCS/DA-CD NPs into the right nostril showed the presence of NPs only in the right olfactory bulb and no morphological tissue damage occurred. Thus, these GCS based NPs could be potentially used as carriers for nose-to-brain DA delivery for the Parkinsons disease treatment.

Inulin-d-α-Tocopherol Succinate (INVITE) Nanomicelles as a Platform for Effective Intravenous Administration of Curcumin

The aim of this work was to evaluate the potential of INVITE-based nanomicelles, an amphiphilic polymer constituted by inulin (INU) and vitamin E (VITE), as a platform for improving the biopharmaceutical properties of hydrophobic drugs. For this purpose, curcumin was selected as a model and curcumin-INVITE nanomicelles were prepared. This drug delivery system was characterized both in vitro for what concerns the physicochemical properties, blood compatibility, and cellular uptake, and in vivo for the evaluation of the pharmacokinetic profile. It was found that these nanomicelles released curcumin in a controlled manner, and they were able to penetrate cellular membrane. Moreover, they showed an improved pharmacokinetic profile after intravenous administration. In conclusion, INVITE micelles might constitute promising nanocarriers for improving the biopharmaceutical performance of hydrophobic drugs.

New Biodegradable Hydrogels Based on Inulin and α,β-Polyaspartylhydrazide Designed for Colonic Drug Delivery: In Vitro Release of Glutathione and Oxytocin.

Succinic derivatives of inulin (INU–SA) with two different degrees of derivatization (20% and 30%, mol/mol) were cross-linked with α,β-polyaspartylhydrazide (PAHy) to obtain INUPAHy hydrogels. Cross-linking was performed using N-ethyl-N-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (NHSS) as coupling agents and by varying the reaction time (4 h, 8 h and 24 h). All samples prepared were characterized by FT-IR analysis and swelling measurements in different media. In vitro assays, performed in the presence of inulinase, demonstrated the degradability of the prepared hydrogels. Cell compatibility was evaluated using Caco-2 cells through both direct and indirect assay. Glutathione (GSH) and oxytocin (OT), both potential agents for the treatment of colonic inflammation, were entrapped into a INUPAHy hydrogel and their release was evaluated in simulated gastrointestinal fluids. The obtained results suggest that GSH- and OT-loaded INUPAHy hydrogels are potentially useful for the oral treatment of inflammatory bowel disease.

A new biodegradable and biocompatible hydrogel with polyaminoacid structure.

The preparation and physicochemical and biological characterization of a novel polyaminoacid hydrogel have been reported. The alpha,beta-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) has been used as a starting polymer for a derivatization reaction with methacrylic anhydride (MA) to give rise to the methacrylate derivative named PHM. Photocrosslinking of PHM has been performed in aqueous solution at 313 nm and in the absence of toxic initiators. PHM-based hydrogel has been characterized by scanning electron microscopy, X-ray diffractometry, swelling measurements in aqueous media; the degradation of PHM-based hydrogel has been evaluated as a function of time in the absence or in the presence of esterase. Besides, the biocompatibility of this hydrogel and of its degradation products has been evaluated by performing in vitro assays on human chronic myelogenous leukaemia cells (K-562), chosen as a model cell line. Finally, ATR-FTIR measurements have showed that interaction between PHM-based hydrogel and each of four plasma proteins (albumin, gamma-globulin, transferrin and fibrinogen) does not cause change in protein conformation thus supporting its potential use as a material to prepare parenteral drug delivery systems.

Inulin based micelles loaded with curcumin or celecoxib with effective anti-angiogenic activity

Curcumin (CUR) and celecoxib (CLX) are two highly hydrophobic drugs which show bioavailability problems due to their poor aqueous solubility. The aim of this study was to encapsulate each of these drugs in micelles based on biodegradable and amphiphilic polymers to investigate their anti-angiogenesis activity. Here we use an amphiphilic polymer, based on two natural substances from renewable resources (Inulin and Vitamin E, INVITE), as a self-assembling system for the drug delivery of CUR and CLX. By the in vivo assay of chick embryo chorioallantoic membrane (CAM) it was assessed that both INVITE-CUR and INVITE-CLX micelles possess remarkable anti-angiogenic activity, while the INVITE micelles alone resulted intrinsically pro-angiogenic. Furthermore, it has been shown that encapsulation of CUR and CLX in INVITE micelles enhances of several magnitudes the water-solubility of CUR and CLX (14·10(5) and 3·10(2) times for CUR and CLX, respectively). These results may have interesting implications not only in anticancer or diabetic maculopathy therapy based on the anti-angiogenesis strategy but also for regenerative medicine where over-production of new vessels is required.

In vitro characterization of 6-Coumarin loaded solid lipid nanoparticles and their uptake by immunocompetent fish cells.

The primary aim of the present work was to evaluate the in vitro uptake of 6-Coumarin (6COUM) loaded solid lipid nanoparticles (SLN) by two gilthead seabream (Sparus aurata L.) cell types: an established cell line (SAF-1 cells) and the primary cultures of head-kidney (HK)-the main haemopoietic organ in fish, equivalent to mammalian bone marrow-leucocytes. For this purpose, after the physicochemical characterization of SLN, the uptake by those immunocompetent fish cells was evaluated using flow cytometry and confocal microscopy. Concomitantly, the uptake of 6-COUM loaded SLN was compared with that achieved with 6-COUM loaded pectin microparticles (MPs), which were selected as a competitor of the delivery carriers. After SLN and MP physicochemical characterization, the results demonstrated that SAF-1 cells were able to internalize high percentages of 6-COUM SLNs when incubated for 4, 8 and 24h, with the highest SLN concentration tested (10 μg/ml). The ability of HK leucocytes to internalize SLN was also found to vary depending on both incubation time and SLN concentration. The highest values of HK leucocytes internalizing SLN particles (around 16%) were detected at the maximum SLN concentration (20 μg/ml) at incubation times of 4 or 8h. Conversely, HK leucocytes were unable to internalize MPs at any tested concentration and incubation time. A possible mechanism explaining the uptake into cells is proposed. The present work constitutes the first approximation to consider SLN as nanocarriers for delivering biologically active substances to fish.

Design, synthesis and evaluation of biotin decorated inulin-based polymeric micelles as long-circulating nanocarriers for targeted drug delivery

Here, long-circulating behaviors of Inulin-based nanomicelles are demonstrated for the first time in vivo. We show the synthesis and evaluation of biotin (BIO)-decorated polymeric INVITE micelles constituted of substances of natural origin, Inulin (INU) and Vitamin E (VITE), as long-circulating carriers for receptor-mediated targeted drug delivery. The resulting INVITE or INVITE-BIO micelles, nanometrically sized, did not reveal any cytotoxicity after 24h of incubation with Caco-2 cells. Moreover, in vitro studies on Caco-2 cells monolayers indicated that the transport of INVITE-BIO micelles was faster than surface unmodified INVITE micelles. In vivo optical imaging studies evidenced that, upon intravenous administration, INVITE-BIO micelles were quantitatively present in the body up to 48h. Instead, after oral administration, the micelles were not found in the systemic circulation but eliminated with the normal intestinal content. In conclusion, INVITE-BIO micelles may enhance drug accumulation in tumor-cells over-expressing the receptor for biotin through receptor mediated endocytosis.