Gallic Acid-Based Hydrogels for Phloretin Intestinal Release: A Promising Strategy to Reduce Oxidative Stress in Chronic Diabetes

Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia caused by abnormalities in insulin secretion and/or action. In patients with diabetes, complications such as blindness, delayed wound healing, erectile dysfunction, renal failure, heart disease, etc., are generally related to an increase in ROS levels which, when activated, trigger hyperglycemia-induced lesions, inflammation and insulin resistance. In fact, extensive cell damage and death occurs mainly due to the effect that ROS exerts at the level of cellular constituents, causing the deterioration of DNA and peroxidation of proteins and lipids. Furthermore, elevated levels of reactive oxygen species (ROS) and an imbalance of redox levels in diabetic patients produce insulin resistance. These destructive effects can be controlled by the defense network of antioxidants of natural origin such as phloretin and gallic acid. For this reason, the objective of this work was to create a nanocarrier (hydrogel) based on gallic acid containing phloretin to increase the antioxidant effect of the two substances which function as fundamental for reducing the mechanisms linked to oxidative stress in patients suffering from chronic diabetes. Furthermore, since the bioavailability problems of phloretin at the intestinal level are known, this carrier could facilitate its release and absorption. The obtained hydrogel was characterized using Fourier transform infrared spectroscopy (FT-IR). Its degree of swelling (a%) and phloretin release were tested under pH conditions simulating the gastric and intestinal environment (1.2, 6.8 and 7.4). The antioxidant activity, inhibiting lipid peroxidation in rat liver microsomal membranes induced in vitro by a free radical source, was evaluated for four hours. All results showed that gallate hydrogel could be applied for releasing intestinal phloretin and reducing the ROS levels.

Hyaluronic Acid-Mediated Phenolic Compound Nanodelivery for Cancer Therapy

Phenolic compounds are bioactive phytochemicals showing a wide range of pharmacological activities, including anti-inflammatory, antioxidant, immunomodulatory, and anticancer effects. Moreover, they are associated with fewer side effects compared to most currently used antitumor drugs. Combinations of phenolic compounds with commonly used drugs have been largely studied as an approach aimed at enhancing the efficacy of anticancer drugs and reducing their deleterious systemic effects. In addition, some of these compounds are reported to reduce tumor cell drug resistance by modulating different signaling pathways. However, often, their application is limited due to their chemical instability, low water solubility, or scarce bioavailability. Nanoformulations, including polyphenols in combination or not with anticancer drugs, represent a suitable strategy to enhance their stability and bioavailability and, thus, improve their therapeutic activity. In recent years, the development of hyaluronic acid-based systems for specific drug delivery to cancer cells has represented a pursued therapeutic strategy. This is related to the fact that this natural polysaccharide binds to the CD44 receptor that is overexpressed in most solid cancers, thus allowing its efficient internalization in tumor cells. Moreover, it is characterized by high biodegradability, biocompatibility, and low toxicity. Here, we will focus on and critically analyze the results obtained in recent studies regarding the use of hyaluronic acid for the targeted delivery of bioactive phenolic compounds to cancer cells of different origins, alone or in combination with drugs.

Polymeric Based Hydrogel Membranes for Biomedical Applications

The development of biomedical applications is a transdisciplinary field that in recent years has involved researchers from chemistry, pharmacy, medicine, biology, biophysics, and biomechanical engineering. The fabrication of biomedical devices requires the use of biocompatible materials that do not damage living tissues and have some biomechanical characteristics. The use of polymeric membranes, as materials meeting the above-mentioned requirements, has become increasingly popular in recent years, with outstanding results in tissue engineering, for regeneration and replenishment of tissues constituting internal organs, in wound healing dressings, and in the realization of systems for diagnosis and therapy, through the controlled release of active substances. The biomedical application of hydrogel membranes has had little uptake in the past due to the toxicity of cross-linking agents and to the existing limitations regarding gelation under physiological conditions, but now it is proving to be a very promising field This review presents the important technological innovations that the use of membrane hydrogels has promoted, enabling the resolution of recurrent clinical problems, such as post-transplant rejection crises, haemorrhagic crises due to the adhesion of proteins, bacteria, and platelets on biomedical devices in contact with blood, and poor compliance of patients undergoing long-term drug therapies.

Solid Lipid Nanoparticles Hydroquinone-Based for the Treatment of Melanoma: Efficacy and Safety Studies

Classical melanoma therapy has several side effects that are responsible for a decrease in the final therapeutic efficacy. It is possible that the drug is degraded before reaching the target site and is metabolized by the body itself, resulting in repeated doses being administered throughout the day and a decrease in patient compliance. Drug delivery systems avoid degradation of the active ingredient, improve release kinetics, prevent the drug from being metabolized before reaching the site of action, and improve the safety and efficacy profiles of adjuvant cancer therapy. The solid lipid nanoparticles (SLNs) based on hydroquinone esterified with stearic acid realized in this work represent a chemotherapeutic drug delivery system that is useful in the treatment of melanoma. The starting materials were characterized by FT-IR and ¹H-NMR, while the SLNs were characterized by dynamic light scattering. In efficacy studies, their ability to influence anchorage-dependent cell proliferation was tested on COLO-38 human melanoma cells. Furthermore, the expression levels of proteins belonging to apoptotic mechanisms were determined by analyzing the role of SLNs in modulating the expression of p53 and p21WAF1/Cip1. Safety tests were conducted to determine not only the pro-sensitizing potential but also the cytotoxicity of SLNs, and studies were conducted to assess the antioxidant and anti-inflammatory activity of these drug delivery.

Green Chemistry Principles for Nano- and Micro-Sized Hydrogel Synthesis

The growing demand for drug carriers and green-technology-based tissue engineering materials has enabled the fabrication of different types of micro- and nano-assemblies. Hydrogels are a type of material that have been extensively investigated in recent decades. Their physical and chemical properties, such as hydrophilicity, resemblance to living systems, swelling ability and modifiability, make them suitable to be exploited for many pharmaceutical and bioengineering applications. This review deals with a brief account of green-manufactured hydrogels, their characteristics, preparations, importance in the field of green biomedical technology and their future perspectives. Only hydrogels based on biopolymers, and primarily on polysaccharides, are considered. Particular attention is given to the processes of extracting such biopolymers from natural sources and the various emerging problems for their processing, such as solubility. Hydrogels are catalogued according to the main biopolymer on which they are based and, for each type, the chemical reactions and the processes that enable their assembly are identified. The economic and environmental sustainability of these processes are commented on. The possibility of large-scale processing in the production of the investigated hydrogels are framed in the context of an economy aimed at waste reduction and resource recycling.

Expanded Polytetrafluoroethylene Membranes for Vascular Stent Coating: Manufacturing, Biomedical and Surgical Applications, Innovations and Case Reports

Coated stents are defined as innovative stents surrounded by a thin polymer membrane based on polytetrafluoroethylene (PTFE)useful in the treatment of numerous vascular pathologies. Endovascular methodology involves the use of such devices to restore blood flow in small-, medium- and large-calibre arteries, both centrally and peripherally. These membranes cross the stent struts and act as a physical barrier to block the growth of intimal tissue in the lumen, preventing so-called intimal hyperplasia and late stent thrombosis. PTFE for vascular applications is known as expanded polytetrafluoroethylene (e-PTFE) and it can be rolled up to form a thin multilayer membrane expandable by 4 to 5 times its original diameter. This membrane plays an important role in initiating the restenotic process because wrapped graft stent could be used as the treatment option for trauma devices during emergency situations and to treat a number of pathological vascular disease. In this review, we will investigate the multidisciplinary techniques used for the production of e-PTFE membranes, the advantages and disadvantages of their use, the innovations and the results in biomedical and surgery field when used to cover graft stents.

Multifunctional Microspheres Based on D-Mannose and Resveratrol for Ciprofloxacin Release

This article describes the preparation, characterization, and performance evaluation of functional microspheres useful for the release of ciprofloxacin. The particles were obtained using D-mannose, a natural aldohexose sugar, and resveratrol, a powerful antioxidant. In particular, the above compounds were initially converted into D-mannose carboxylate and resveratrol methacrylate and, therefore, subjected to an esterification reaction. The resulting product was used for the preparation of the microspheres which were characterized by light scattering, FT-IR spectrophotometry and scanning electron microscopy (SEM). Subsequently, their degree of bloating was evaluated at pH 1.2 to simulate the pH of the stomach, at pH 6.8 and pH 7.4 to mimic the intestinal environment. The antibiotic ciprofloxacin was then loaded into the microspheres, with an encapsulation efficiency of 100%. The cumulative amount of drug released was 55% at pH 6.8 and 99% at pH 7.4. The tests conducted to evaluate the antibacterial activity demonstrated the ability of the microspheres obtained to inhibit the growth of Escherichia coli. The antioxidant efficacy, due to the presence of resveratrol in their structure, was confirmed using rat liver microsomal membranes. The results obtained have highlighted how the microspheres based on D-mannose and resveratrol can be considered promising multifunctional vectors useful in the treatment of intestinal and urinary infections.

Production of α-Tocopherol–Chitosan Nanoparticles by Membrane Emulsification

α-tocopherol (α-T) has the highest biological activity with respect to the other components of vitamin E; however, conventional formulations of tocopherol often fail to provide satisfactory bioavailability due to its hydrophobic characteristics. In this work, α-tocopherol-loaded nanoparticles based on chitosan were produced by membrane emulsification (ME). A new derivative was obtained by the cross-linking reaction between α-T and chitosan (CH) to preserve its biological activity. ME was selected as a method for nanoparticle production because it is recognized as an innovative and sustainable technology for its uniform-particle production with tuned sizes and high encapsulation efficiency (EE%), and its ability to preserve the functional properties of bioactive ingredients operating in mild conditions. The reaction intermediates and the final product were characterized by 1HNMR, Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC), while the morphological and dimensional properties of the nanoparticles were analyzed using electronic scanning microscopy (SEM) and dynamic light scattering (DLS). The results demonstrated that ME has high potential for the development of α-tocopherol-loaded nanoparticles with a high degree of uniformity (PDI lower than 0.2), an EE of almost 100% and good mechanical strength, resulting in good candidates for the production of functional nanostructured materials for drug delivery. In addition, the chemical bonding between chitosan and α-tocopherol allowed the preservation of the antioxidant properties of the bioactive molecule, as demonstrated by an enhanced antioxidant property and evaluated through in vitro tests, with respect to the starting materials.

Deep Eutectic Solvents for Improving the Solubilization and Delivery of Dapsone

Owing to a growing awareness toward environmental impact, the use of safer and eco-friendly solvents like deep eutectic solvents (DESs), has recently undergone important growth in the pharmaceutical field, with regard to their application as non-aqueous liquid administration vehicles, since they do not carry the same risks of toxicity and handling as traditional organic solvents. Major attention has been given to the development of advantageous transdermal drug delivery systems, because of their ease of use and better acceptability. Here, we report the use of two different DESs, based on choline chloride, used as hydrogen bond acceptor (HBA), and ascorbic acid or propylene glycol, used as hydrogen bond donors (HBDs), able to enhance the solubility and the topical delivery of dapsone, representing a class IV drug. The interactions between the DESs’ components and the drug were studied by performing DSC, FT-IR, and NMR analysis of the eutectic systems and the pure drug, confirming the establishment of H-bonds between the drug and the DESs’ components. Diffusion and permeability studies, carried out in a Franz cell, showed an increase in permeability, highlighting the great potential of DESs as dissolution and permeation enhancers in the development of novel and more effective drug delivery systems in topical administration.

Novel Nanoparticles Based on N,O-Carboxymethyl Chitosan-Dopamine Amide Conjugate for Nose-to-Brain Delivery

A widely investigated approach to bypass the blood brain barrier is represented by the intranasal delivery of therapeutic agents exploiting the olfactory or trigeminal connections nose-brain. As for Parkinson’s disease (PD), characterized by dopaminergic midbrain neurons degeneration, currently there is no disease modifying therapy. Although several bio-nanomaterials have been evaluated for encapsulation of neurotransmitter dopamine (DA) or dopaminergic drugs in order to restore the DA content in parkinsonian patients, the premature leakage of the therapeutic agent limits this approach. To tackle this drawback, we undertook a study where the active was linked to the polymeric backbone by a covalent bond. Thus, novel nanoparticles (NPs) based on N,O-Carboxymethylchitosan-DA amide conjugate (N,O-CMCS-DA) were prepared by the nanoprecipitation method and characterized from a technological view point, cytotoxicity and uptake by Olfactory Ensheating Cells (OECs). Thermogravimetric analysis showed high chemical stability of N,O-CMCS-DA NPs and X-ray photoelectron spectroscopy evidenced the presence of amide linkages on the NPs surface. MTT test indicated their cytocompatibility with OECs, while cytofluorimetry and fluorescent microscopy revealed the internalization of labelled N,O-CMCS-DA NPs by OECs, that was increased by the presence of mucin. Altogether, these findings seem promising for further development of N,O-CMCS-DA NPs for nose-to-brain delivery application in PD.

Green solvents for the formation of amide linkages

The formation of the amide bond is among the most commonly performed transformations in the pharmaceutical industry and the wider chemical industry. The current methods for its installation in organic compounds frequently rely on the use of large amounts of organic solvents, mainly N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dichloromethane (DCM), which have been associated with adverse environmental and health concerns over the last decades. This fact led academia and industry to make significant efforts toward the development of synthetic routes with the aim to avoid, reduce or replace the use of hazardous solvents. The present review fits into this framework and discusses the literature existing over the past ten years on strategies for reducing and replacing hazardous solvents, focusing on the use of biobased and neoteric solvents, such as ionic liquids and deep eutectic solvents (ILs and DESs, respectively), and on the reaction media that proved to be greener alternatives for amide bond formation.

Gel-Based Materials for Ophthalmic Drug Delivery

The most common route of administration of ophthalmic drugs is the topical route because it is convenient, non-invasive, and accessible to all patients. Unfortunately, drugs administered topically are not able to reach effective concentrations. Moreover, their bioavailability must be improved to decrease the frequency of administrations and their side effects, and to increase their therapeutic efficiency. For this purpose, in recent decades, particular attention has been given to the possibility of developing prolonged-release forms that are able to increase the precorneal residence time and decrease the loss of the drug due to tearing. Among these forms, gel-based materials have been studied as an ideal delivery system because they are an extremely versatile class with numerous prospective applications in ophthalmology. These materials are used in gel eye drops, in situ gelling formulations, intravitreal injections, and therapeutic contact lenses. This review is intended to describe gel-based materials and their main applications in ophthalmology.

Valorization of Tomato Waste as a Source of Carotenoids

Fast-accumulating scientific evidence from many studies has revealed that fruits and vegetables are the main source of bioactive compounds; in most cases, wastes and byproducts generated by the food processing industry present similar or a higher content of antioxidant compounds. In recent years, the ever-growing amount of agricultural and food wastes has raised serious concerns from an environmental point of view. Therefore, there is an increasing interest in finding new ways for their processing toward safely upgrading these wastes for recovering high-value-added products with a sustainable approach. Among food waste, the abundance of bioactive compounds in byproducts derived from tomato suggests possibility of utilizing them as a low-cost source of antioxidants as functional ingredients. This contribution gives an overview of latest studies on the extraction methods of carotenoids from tomato waste, along with an evaluation of their antioxidant activity, as well as their industrial applications.

Characterization of a hyaluronic acid and folic acid-based hydrogel for cisplatin delivery: Antineoplastic effect in human ovarian cancer cells in vitro

We successfully prepared and characterized a hyaluronic acid- and folic acid-based hydrogel for the delivery of cisplatin (GEL-CIS) with the aim to induce specific and efficient incorporation of CIS into ovarian cancer (OC) cells, improve its antineoplastic effect and avoid CIS-resistance. The slow and controlled release of the drug from the polymeric network and its swelling degree at physiologic pH suggested its suitability for CIS delivery in OC. We compared here the effects of pure CIS to that of GEL-CIS on human OC cell lines, either wild type or CIS-resistant, in basal conditions and in the presence of macrophage-derived conditioned medium, mimicking the action of tumor-associated macrophages in vivo. GEL-CIS inhibited OC cell growth and migration more efficiently than pure CIS and modulated the expression of proteins involved in the Epithelial Mesenchymal Transition, a process playing a key role in OC metastatic spread and resistance to CIS.

Polymeric Biomaterials for the Treatment of Cardiac Post-Infarction Injuries

Cardiac regeneration aims to reconstruct the heart contractile mass, preventing the organ from a progressive functional deterioration, by delivering pro-regenerative cells, drugs, or growth factors to the site of injury. In recent years, scientific research focused the attention on tissue engineering for the regeneration of cardiac infarct tissue, and biomaterials able to anatomically and physiologically adapt to the heart muscle have been proposed as valuable tools for this purpose, providing the cells with the stimuli necessary to initiate a complete regenerative process. An ideal biomaterial for cardiac tissue regeneration should have a positive influence on the biomechanical, biochemical, and biological properties of tissues and cells; perfectly reflect the morphology and functionality of the native myocardium; and be mechanically stable, with a suitable thickness. Among others, engineered hydrogels, three-dimensional polymeric systems made from synthetic and natural biomaterials, have attracted much interest for cardiac post-infarction therapy. In addition, biocompatible nanosystems, and polymeric nanoparticles in particular, have been explored in preclinical studies as drug delivery and tissue engineering platforms for the treatment of cardiovascular diseases. This review focused on the most employed natural and synthetic biomaterials in cardiac regeneration, paying particular attention to the contribution of Italian research groups in this field, the fabrication techniques, and the current status of the clinical trials.

Gelatin and Glycerine-Based Bioadhesive Vaginal Hydrogel

AIM

The work's aim was the preparation and characterization of a hydrogel based on gelatin and glycerine, useful for site-specific release of benzydamine, an anti-inflammatory drug, able to attenuate the inflammatory process typical of the vaginal infection.

OBJECTIVE

The obtained hydrogel has been characterized by Electronic Scanning Microscopy (SEM) and Differential Scanning Calorimetry (DSC). In addition, due to the precursor properties, the hydrogel exhibits a relevant mucoadhesive activity.

METHODS

The swelling degree was evaluated at two different pHs and at defined time intervals. In particular, phosphate buffers were used at pH 6.6, in order to mimic the typical conditions of infectious diseases at the vaginal level, particularly for HIV-seropositive pregnant women, and pH 4.6, to simulate the physiological environment.

RESULTS

The obtained results revealed that the hydrogel swells up well at both pHs.

CONCLUSION

Release studies conducted at both pathological and physiological pHs have shown that benzydamine is released at the level of the vaginal mucosa in a slow and gradual manner. These data support the hypothesis of the hydrogel use for the site-specific release of benzydamine in the vaginal mucosa.

Biomaterials for Drugs Nose-Brain Transport: A New Therapeutic Approach for Neurological Diseases

In the last years, neurological diseases have resulted in a global health issue, representing the first cause of disability worldwide. Current therapeutic approaches against neurological disorders include oral, topical, or intravenous administration of drugs and more invasive techniques such as surgery and brain implants. Unfortunately, at present, there are no fully effective treatments against neurodegenerative diseases, because they are not associated with a regeneration of the neural tissue but rather act on slowing the neurodegenerative process. The main limitation of central nervous system therapeutics is related to their delivery to the nervous system in therapeutic quantities due to the presence of the blood-brain barrier. In this regard, recently, the intranasal route has emerged as a promising administration site for central nervous system therapeutics since it provides a direct connection to the central nervous system, avoiding the passage through the blood-brain barrier, consequently increasing drug cerebral bioavailability. This review provides an overview of the nose-to-brain route: first, we summarize the anatomy of this route, focusing on the neural mechanisms responsible for the delivery of central nervous system therapeutics to the brain, and then we discuss the recent advances made on the design of intranasal drug delivery systems of central nervous system therapeutics to the brain, focusing in particular on stimuli-responsive hydrogels.

Chitosan Membranes Filled with Cyclosporine A as Possible Devices for Local Administration of Drugs in the Treatment of Breast Cancer

The aim of this work is the design, preparation and characterization of membranes based on cyclosporine A (CsA) and chitosan carboxylate (CC) to be used as an implantable subcutaneous medical device for a prolonged therapeutic effect in the treatment of breast cancer. The choice to use CsA is due to literature data that have demonstrated its possible antitumor activity on different types of neoplastic cells. To this end, CsA was bound to CC through an amidation reaction to obtain a prodrug to be dispersed in a chitosan-based polymeric membrane. The reaction intermediates and the final product were characterized by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (¹H-NMR). Membranes were analyzed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The data obtained showed the effective formation of the amide bond between CsA and CC and the complete dispersion of CsA inside the polymeric membrane. Furthermore, preliminary tests, conducted on MDA-MB-231, a type of breast cancer cell line, have shown a high reduction in the proliferation of cancer cells. These results indicate the possibility of using the obtained membranes as an interesting strategy for the release of cyclosporin-A in breast cancer patients.

Nose-to-brain delivery: A comparative study between carboxymethyl chitosan based conjugates of dopamine

Herein, the synthesis of a novel polymeric conjugate N,O-CMCS-Dopamine (DA) based on an amide linkage is reported. The performances of this conjugate were compared with those of an analogous N,O-CMCS-DA ester conjugate previously studied (Cassano et al., 2020) to gain insight into their potential utility for Parkinson's disease treatment. The new amide conjugate was synthesized by standard carbodiimide coupling procedure and characterized by FT-IR, ¹H NMR spectroscopies and thermal analysis (Differential Scanning Calorimetry). In vitro mucoadhesive studies in simulated nasal fluid (SNF) evidenced high adhesive effect of both ester and amide conjugates. Results demonstrated that the amide conjugate exerted an important role to prevent DA spontaneous autoxidation both under stressed conditions and physiological mimicking ones. MTT test indicated cytocompatibility of the amide conjugate with Olfactory Ensheating Cells (OECs), which were shown by cytofluorimetry to internalize efficiently the conjugate. Overall, among the two conjugates herein studied, the N,O-CMCS-DA amide conjugate seems a promising candidate for improving the delivery of DA by nose-to-brain administration.

Recent Advances in Nanotechnology for the Treatment of Melanoma

Melanoma is one of the most aggressive forms of skin cancer, with few possibilities for therapeutic approaches, due to its multi-drug resistance and, consequently, low survival rate for patients. Conventional therapies for treatment melanoma include radiotherapy, chemotherapy, targeted therapy, and immunotherapy, which have various side effects. For this reason, in recent years, pharmaceutical and biomedical research has focused on new sito-specific alternative therapeutic strategies. In this regard, nanotechnology offers numerous benefits which could improve the life expectancy of melanoma patients with very low adverse effects. This review aims to examine the latest advances in nanotechnology as an innovative strategy for treating melanoma. In particular, the use of different types of nanoparticles, such as vesicles, polymers, metal-based, carbon nanotubes, dendrimers, solid lipid, microneedles, and their combination with immunotherapies and vaccines will be discussed.

Nano- and Micro-Technologies Applied to Food Nutritional Ingredients

New technologies are currently investigated to improve the quality of foods by enhancing their nutritional value, freshness, safety, and shelf-life, as well as by improving their tastes, flavors and textures. Moreover, new technological approaches are being explored, in this field, to address nutritional and metabolism-related diseases (i.e., obesity, diabetes, cardiovascular diseases), to improve targeted nutrition, in particular for specific lifestyles and elderly population, and to maintain the sustainability of food production. A number of new processes and materials, derived from micro- and nano-technology, have been used to provide answers to many of these needs and offer the possibility to control and manipulate properties of foods and their ingredients at the molecular level. The present review focuses on the importance of micro- and nano-technology in the food and nutritional sector and, in particular, provides an overview of the micro- and nano-materials used for the administration of nutritional constituents essential to maintain and improve health, as well as to prevent the development and complications of diseases.

Synthesis and characterization of novel chitosan-dopamine or chitosan-tyrosine conjugates for potential nose-to-brain delivery

This work aims to the synthesis of novel carboxylated chitosan-dopamine (DA) and -tyrosine (Tyr) conjugates as systems for improving the brain delivery of the neurotransmitter DA following nasal administration. For this purpose, ester or amide conjugates were synthesized by N,N-dicyclohexylcarbodiimide (DCC) mediated coupling reactions between the appropriate N-tert-butyloxycarbonyl (Boc) protected starting polymers N,O-carboxymethyl chitosan and 6-carboxy chitosan and DA or O-tert-Butyl-L-tyrosine-tert-butyl ester hydrochloride. The resulting conjugates were characterized by FT-IR and ¹H- and ¹³C NMR spectroscopies and their in vitro mucoadhesive properties in simulated nasal fluid (SNF), toxicity and uptake from Olfactory Ensheathing Cells (OECs) were assessed. Results demonstrated that N,O-carboxymethyl chitosan-DA conjugate was the most mucoadhesive polymer in the series examined and, together with the 6-carboxy chitosan-DA-conjugate were able to release the neurotransmitter in SNF. The MTT assay showed that the starting polymers as well as all the prepared conjugates in OECs resulted not toxic at any concentration tested. Likewise, the three synthesized conjugates were not cytotoxic as well. Cytofluorimetric analysis revealed that the N,O-carboxymethyl chitosan DA conjugate was internalized by OECs in a superior manner at 24 h as compared with the starting polymer. Overall, the N,O-CMCS-DA conjugate seems promising for improving the delivery of DA by nose-to-brain administration.

Viscosified Solid Lipidic Nanoparticles Based on Naringenin and Linolenic Acid for the Release of Cyclosporine A on the Skin

Psoriasis is one of the most common human skin disorders. Although its pathogenesis is complex and not completely know, the hyperactivation of the immune system seem to have a key role. In this regard, among the most effective systemic therapeutics used in psoriasis, we find cyclosporine, an immunosuppressive medication. However, one of the major problems associated with the use of cyclosporine is the occurrence of systemic side effects such as nephrotoxicity, hypertension, etc. The present work fits in this context and its aim is the design of suitable platforms for cyclosporine topical release in psoriasis treatment. The main objective is to achieve local administration of cyclosporine in order to reduce its systemic absorption and, consequently, its side effects. In order to improve dermal penetration, solid lipid nanoparticles (SLNs) are used as carriers, due to their lipophilicity and occlusive properties, and naringenin and linolenic acid are chosen, due to their properties, as starting materials for SLNs design. In order to have dermatological formulations and further modulate drug release, SLNs are incorporated in several topical vehicles obtaining gels with different degree of lipophilicity. Potential applications for psoriasis treatment were evaluated by considering the encapsulation efficiency, release profiles, in vitro skin permeation, and anti-inflammatory effects.

Special Issue on Designing Hydrogels for Controlled Drug Delivery: Guest Editors' Introduction

Hydrogels have received growing attention in recent years as materials for drug delivery systems (DDS), because they are biocompatible and nontoxic [...].

Strategies for Hyaluronic Acid-Based Hydrogel Design in Drug Delivery

Hyaluronic acid (HA) is a natural, linear, endogenous polysaccharide that plays important physiological and biological roles in the human body. Nowadays, among biopolymers, HA is emerging as an appealing starting material for hydrogels design due to its biocompatibility, native biofunctionality, biodegradability, non-immunogenicity, and versatility. Since HA is not able to form gels alone, chemical modifications, covalent crosslinking, and gelling agents are always needed in order to obtain HA-based hydrogels. Therefore, in the last decade, different strategies for the design of physical and chemical HA hydrogels have been developed, such as click chemistry reactions, enzymatic and disulfide crosslinking, supramolecular assembly via inclusion complexation, and so on. HA-based hydrogels turn out to be versatile platforms, ranging from static to smart and stimuli-responsive systems, and for these reasons, they are widely investigated for biomedical applications like drug delivery, tissue engineering, regenerative medicine, cell therapy, and diagnostics. Furthermore, the overexpression of HA receptors on various tumor cells makes these platforms promising drug delivery systems for targeted cancer therapy. The aim of the present review is to highlight and discuss recent advances made in the last years on the design of chemical and physical HA-based hydrogels and their application for biomedical purposes, in particular, drug delivery. Notable attention is given to HA hydrogel-based drug delivery systems for targeted therapy of cancer and osteoarthritis.

Nanomedicine-based formulations containing ω-3 polyunsaturated fatty acids: potential application in cardiovascular and neoplastic diseases

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are dietary factors involved in the prevention of cardiovascular, inflammatory, and neoplastic diseases. A multidisciplinary approach – based on recent findings in nutritional science, lipid biochemistry, biotechnology, and biology of inflammation and cancer – has been recently employed to develop ω-3 PUFA-containing nanoformulations with an aim to protect these fatty acids from degradation, increase their bioavailability and delivery to target tissues, and, thus, enhance their bioactivity. In some cases, these nanoformulations were designed to administer ω-3 PUFAs in combination with other nutraceuticals or conventional/innovative drugs. The aim of this strategy was to increase the activities of the compounds contained in the nanoformulation and to reduce the adverse effects often induced by drugs. We herein analyze the results of papers evaluating the potential use of ω-3 PUFA-containing nanomaterials in fighting cardiovascular diseases and cancer. Future directions in this field of research are also provided.

Hemostatic gauze based on chitosan and hydroquinone: preparation, characterization and blood coagulation evaluation

This work concerns on the preparation and performance evaluation of a new chitosan hydroquinone based gauze for hemostatic use. Chitosan and hydroquinone were firstly connected by etherification and then linked to the pre-carboxylate gauze. The functionalized material and the chitosan-hydroquinone ether were characterized by Fourier Transform Infrared (FT-IR) Spectroscopy and Differential Scanning Calorimetry (DSC). FT-IR results showed that an esterification occurred on carboxylic group of the gauze. The gauze functionalization degree was also evaluated by volumetric analysis. The ether hydroquinone content was obtained by the Folin test. Moreover, the linkage between hydroquinone and chitosan was confirmed by nuclear magnetic resonance (NMR). The hemostatic activity of functionalized gauze was evaluated by dynamic blood clotting assays. The obtained results showed that the prepared material can shorten the blood clotting time and induce the adhesion and activation of platelets. Finally, swelling characteristic of the new gauze was evaluated to confirm its high capacity to absorb the blood.

α-Tocopheryl linolenate solid lipid nanoparticles for the encapsulation, protection, and release of the omega-3 polyunsaturated fatty acid: in vitro anti-melanoma activity evaluation

The main target of this study was the preparation, characterization and antioxidant activity evaluation of α-tocopheryl linolenate based solid lipid nanoparticles (SLNs-TL), able to incorporate omega-3 α-linolenic acid, useful for the treatment of melanoma, a type of skin cancer. In particular, α-linolenic acid was successfully derivatized with α-tocopherol and the obtained compound was characterized by Fourier transform infrared (FT-IR) and by ¹H NMR to confirm the ester linkage. Both the empty SLNs-TL that SLNs-TL-LIN, containing omega-3-linolenic acid, were prepared through the technique of the microemulsion. The nanoparticles were characterized for entrapment efficiency, size and shape. Their antioxidant activity was investigated in rat liver microsomal membranes in inhibiting the lipid peroxidation induced by tert-butyl hydroperoxide (tert-BOOH), which endogenously produces alkoxyl radicals by Fenton reactions. The obtained results indicate that the α-tocopherol, linked by ester bond to α-linolenic acid, maintains an excellent antioxidant activity. The encapsulation efficiency was equal to 77% and the polydispersity index 0.198 indicating a good dimensional distribution. Furthermore, the nanoparticles were tested in vitro for their cytotoxic activity against human melanoma cancer cell line C32. Both empty SLNs-TL and loaded SLNs-TL-LIN showed a high biological activity, being more effective than α-linolenic acid and α-tocopherol. The results indicated that these nanoparticles could provide the delivery and the protection of unstable molecules, such as α-linolenic acid, from degradation induced by mechanisms of oxidative stress.

Role of β-catenin signaling in the anti-invasive effect of the omega-3 fatty acid DHA in human melanoma cells

BACKGROUND

We previously found that docosahexaenoic acid (DHA), a dietary polyunsaturated fatty acid present at high level in fatty fish, inhibited cell growth and induced differentiation of melanoma cells in vitro by increasing nuclear β-catenin content. An anti-neoplastic role of nuclear β-catenin was suggested in melanoma, and related to the presence in the melanocyte lineage of the microphtalmia transcription factor (MITF), which interferes with the transcription of β-catenin/TCF/LEF pro-invasive target genes.

OBJECTIVE

In the present work we investigated if DHA could inhibit the invasive potential of melanoma cells, and if this effect could be related to DHA-induced alterations of the Wnt/β-catenin signaling, including changes in MITF expression.

METHODS

WM115 and WM266-4 human melanoma, and B16-F10 murine melanoma cell lines were used. Cell invasion was evaluated by Wound Healing and Matrigel transwell assays. Protein expression was analyzed by Western Blotting and β-catenin phosphorylation by immunoprecipitation. The role of MITF in the anti-invasive effect of DHA was analyzed by siRNA gene silencing.

RESULTS

We found that DHA inhibited anchorage-independent cell growth, reduced their migration/invasion in vitro and down-regulated several Matrix Metalloproteinases (MMP: MMP-2, MT1-MMP and MMP-13), known to be involved in melanoma invasion. We related these effects to the β-catenin increased nuclear expression and PKA-dependent phosphorylation, as well as to the increased expression of MITF.

CONCLUSION

The data obtained further support the potential role of dietary DHA as suppressor of melanoma progression to invasive malignancy through its ability to enhance MITF expression and PKA-dependent nuclear β-catenin phosphorylation.

Novel microspheres based on triterpene saponins from the roots of Physospermum verticillatum (Waldst & Kit) (Apiaceae) for the improvement of gemcitabine release

Objectives

This study concerns the preparation and characterization of microspheres based on a mixture of triterpene saponins, from Physospermum verticillatum (Waldst & Kit), as a carrier for the specific release of gemcitabine.

Methods

Triterpene saponins were derivatized with acrylic acid. The obtained polymerizable product was characterized by Fourier transform infrared to confirm the ester linkage. Then, spherical microparticles were prepared by suspension radical copolymerization and impregnated with gemcitabine.

Key findings

Microspheres exhibited a mean diameter of 2.7 μ. The swelling studies showed that particles swell most at pH 6.2, typical of the tumour pathology, than at pH 7.4, miming physiological conditions. The microspheres were loaded with gemcitabine (LE 72.2%). Their release profile showed an initial dot of around 24% and a further release for 24 h.

Conclusions

This carrier could be potentially release the drug in the lung, as a function of different pHs between tumour cells and healthy, reducing the systemic drug toxicity, allowing the reduction of the doses number, increasing the drug half-life and eliminating the problems related to the fast clearance of gemcitabine administration.

A new pro-prodrug aminoacid-based for trans-ferulic Acid and silybin intestinal release

The aim of this work was the preparation and characterization of a pro-prodrug able to simultaneously transport silybin, a drug possessing various pharmacological effects, and trans-ferulic acid, a known antioxidant. More specifically, l-phenylalanine-N-(4-hydroxy-3-methoxy-phenyl) prop-2-en-O-(2R,3R)-3,5,7-trihydroxy-2-((2R,3R)-3-(4-hydroxy-3-methoxyphenyl)-2-(hydroxymethyl)-2,3-dihydro-benzo-(1,4)-dioxin-6-yl)croman-4-one was synthesized by using the aminoacid l-phenylalanine (l-Phe) as carrier. Indeed, l-Phe is characterized by an intrinsic chemical reactivity due to the presence of an amino group, placed on the chiral center, and of a carboxylic group. The synthesis has been characterized first by adding silybin by means of carboxylic group and then, with the aim to confer antioxidant properties to this new carrier, by linking trans-ferulic acid to l-Phe via amino group. The so obtained derivative was then characterized by FT-IR, and ¹H-NMR spectroscopies. Furthermore, its ability to inhibit lipid peroxidation induced by tert-butyl hydroperoxide in rat liver microsomes, was evaluated. The 1,1-diphenyl-2-picrylhydrazyl radical-scavenging effect, was also assessed. The release of silybin and trans-ferulic acid was determined in simulated gastric and intestinal fluids over the time. The results showed that the covalent bond between both (i) silybin; or (ii) trans-ferulic acid and the amino acid was degraded by enzymatic reactions. In addition, the pro-prodrug, showed strong antioxidant and scavenger activities. Due to these properties, this new pro-prodrug could be applied for the treatment of intestinal pathologies and it might improve the therapeutic potential of silybin which is strongly limited by its low solubility.

Anticancer activity of a hydrogel containing folic acid towards MCF-7 and MDA-MB-231 cells

AIM

The aim of the present study was to prepare a hydrogel, based on ellagic acid and glycine, embedded with folic acid, as a subcutaneous implant for the treatment of breast cancer. The function of folic acid is to selectively and actively target tumor cells which are well-known to overexpress folic acid receptors on their surface.

MATERIALS AND METHODS

A pro-drug based on L-glycine and ellagic acid, was functionalized with a polymerizable group and loaded with folic acid to make it more natural, non-toxic, compatible and specific for the site of action. Cytotoxicity against MCF-7 cells was also evaluated. Release studies of folic acid were conducted on aliquots of hydrogel at different pH (6.2 and 7.4) and time-points (1, 6, 12 and 24 h) using a shaking water bath at 37°C (body temperature).

RESULTS

Our results show that folic acid release by the hydrogel is characterized by a slow kinetic release, especially at pH 6.2. Moreover, it was evidenced that the exposure of human breast cancer cells to ellagic acid-based hydrogel containing folic acid significantly reduced cell viability.

Isoniazid-gelatin conjugate microparticles containing rifampicin for the treatment of tuberculosis

Objectives 

In this work, a new polymeric microparticle system based on gelatin covalently bound to isoniazid (ISN) and containing rifampicin (RFP) was prepared by spray-drying technique. Microparticle aptitude to nebulisation and their capability of interacting with A549, alveolar basal epithelial cells, were evaluated in vitro.

Methods

Microparticles were obtained by spray drying, and their morphology, size, zeta potential, thermotropic behaviour and nebulisation ability were evaluated.

Key findings 

Microparticles were positively charged with a mean size of 4.88 ± 0.3 μm. Microspheres were able to incorporate both RFP and ISN: encapsulation efficiency was 51 ± 6% and 22 ± 1%, respectively. X-ray diffraction study showed a new extensive and flattened diffraction peak providing evidence that the drugs were dispersed into the microparticles. Differential scanning calorimetry analysis confirmed effective interactions between gelatin and drug molecules by the presence of new transition peaks. Fifty-nine per cent of used microparticles were aerosolised. In-vitro toxicity studies on A549 alveolar basal epithelial cells showed that microparticles decreased cytotoxicity in comparison with the RFP solution. Laser scanning confocal microscopy observation confirmed that fluorescent probes delivered by microparticles are efficiently internalised in A549 cells.

Conclusions 

Overall, microparticles based on gelatin covalently bound to ISN and containing RFP showed a promising behaviour for pulmonary drug delivery.

Trans-ferulic acid-based solid lipid nanoparticles and their antioxidant effect in rat brain microsomes

In this study, stearic acid- and stearyl ferulate-based solid lipid nanoparticles containing trans-ferulic acid (SLN-FA and SLN-SF-FA, respectively), were prepared and characterized for loading efficiency, size and shape. In addition, by using rat brain microsomes, we evaluated in vitro the antioxidant activity of these formulations against three well known initiators of lipid peroxidation, such as AAPH, NADPH/ADP-Fe(3+) and SIN-1 which in turn generate the peroxyl and perferryl radicals as well as peroxynitrite, respectively. Commercially available FA and its ethyl ester (FAEE) were used as comparators. Both SLN-FA and SLN-SF-FA dose-dependently reduced lipid peroxidation induced by the three oxidants. Interestingly, SLN-SF-FA displayed greater efficacy (EC50) and potency (maximal activity) against AAPH- and NADPH/ADP-Fe(3+)-induced lipid peroxidation. Our results support the idea that this new formulations could facilitate the uptake of FA by the cells because of their lipophilic structure, thus increasing FA bioavailability. Furthermore, stearyl ferulate-based nanoparticles could prevent the degradation of FA entrapped on their structure, making FA almost entirely available to explicate its antioxidant power once released.

Ciprofloxacin-collagen conjugate in the wound healing treatment

The synthesis of a novel functional biomaterial for wound healing treatment was carried out by adopting a free-radical grafting procedure in aqueous media. With this aim, ciprofloxacin (CFX) was covalently incorporated into collagen (T1C) chains employing an ascorbic acid/hydrogen peroxide redox pair as biocompatible initiator system. The covalent insertion of CFX in the polymeric chains was confirmed by FT-IR and UV analyses, while an antibacterial assay demonstrated the activity of the synthesized conjugate against Staphylococcusaureus and Escherichia coli, microorganisms that commonly infect wounds. A catechin blended conjugate was also tested in order to evaluate the ability to influence fibroblast cell growth. The observed antibacterial activity and stimulation of fibroblast growth support the applicability of CFX-T1C conjugate in wound treatment encouraging the healing process.

Synthesis, characterization and in-vitro antitubercular activity of isoniazid-gelatin conjugate

OBJECTIVES

A novel and simple method to synthesize antitubercular-protein conjugate by solid phase synthesis was developed employing a carboxypolystyrene resin. The aim was to covalently bind a drug with antitubercular activity, isoniazid, to a biomacromolecule, gelatin, widely used in the pharmaceutical, cosmetic and food industry.

METHODS

Calorimetric and (1) H NMR analyses were performed to verify the bond formation between the antitubercular drug and gelatin. After absorption isoniazid delivers toxic metabolites and so an oxidation test with tert-butyl hydroperoxide was performed to assess the amount of toxic metabolites released from the prodrug (gelatin linked to isoniazid), compared with isoniazid itself.

KEY FINDINGS

  Spectrophotometric analysis revealed that the protein derivative was an excellent isoniazid prodrug since there was a 40% reduction in release of toxic metabolites (isonicotinic acid) by the prodrug. The results clearly showed that antitubercular moieties, covalently linked to a natural polymer, allowed the introduction of peculiar features for specific pharmaceutical applications into the macromolecule. In addition, antitubercular activity of the new polymer was determined by Middlebrook 7H11 medium against Mycobacterium tuberculosis complex.

CONCLUSIONS

The new isoniazid-gelatin conjugate showed significant antitubercular activity and for this reason should be useful as an efficacious tool in the treatment of tuberculosis.

A new approach for the evaluation of niosomes as effective transdermal drug delivery systems

The central motivation for this study was to evaluate if the increased hydrophilic drug permeation across the skin, which is always observed in presence of vesicular systems, is dependent on the structural organization of niosomes, that are used to transport the active molecules, or if it is only dependent on the surfactant dual nature. To answer this question, non-ionic surfactants belonging to the class of Pluronic and sucrose esters were used both as components of niosomal systems or in the form of sub-micellar solutions. The obtained niosomes were characterized by their entrapment efficiency, size and morphology. The enhancing effect of niosomes on the ex vivo percutaneous penetration of a model drug was investigated using a Franz-type diffusion chamber and compared to that obtained by using sub-micellar solution of surfactant or achieving pretreatment of the skin with surfactants' sub-micellar solution or empty niosomes. The results suggest that the surfactants used in this study could be considered as percutaneous permeation enhancers only when they are in the form of drug-loaded vesicular systems: no percutaneous promotion was achieved by using sub-micellar solution containing free Sulfadiazine sodium salt or performing pretreatment with empty niosomes or sub-micellar solutions of the surfactant. In our experiments, only niosomes act as effective transdermal drug delivery systems.

Docosahexaenoic acid reverts resistance to UV-induced apoptosis in human keratinocytes: involvement of COX-2 and HuR

The dramatic increase in the incidence of nonmelanoma skin cancer over the last decades has been related to the augmented exposure to ultraviolet (UV) radiation (UVR). It is known that apoptosis is induced as a protective mechanism after the acute irradiation of keratinocytes, whereas apoptotic resistance and carcinogenesis may follow the chronic exposure to UVR. We found that not all the human keratinocytes lines studied underwent apoptosis following acute exposure to UVR (10-60 mJ/cm(2)). Whereas UVR induced apoptosis in the HaCaT cells, NCTC 2544 and nr-HaCaT cells showed apoptosis resistance. The cytokeratin pattern of the apoptosis-resistant cells indicated that they possessed a degree of differentiation lower than that of HaCaT cells. They also showed an enhanced expression of cyclooxygenase-2 (COX-2), an early marker of carcinogenesis in various tissues, including skin. n-3 polyunsaturated fatty acids have drawn increasing interest as nutritional factors with the potential to reduce UVR carcinogenesis, and since they are apoptosis inducers and COX-2 inhibitors in cancer cells, we investigated the ability of n-3 polyunsaturated fatty acids to influence the resistance to UVR-induced apoptosis in keratinocytes. We observed that docosahexaenoic acid (DHA) reverted the resistance of nr-HaCaT cells to UVR-induced apoptosis, increasing the Bax/Bcl-2 ratio and caspase-3 activity, and reduced COX-2 levels by inhibiting the expression of the human antigen R (HuR), a known COX-2 mRNA stabilizer in keratinocytes. The transfection of nr-HaCaT cells with HuR siRNA mimicked the proapoptotic effect of DHA. Overall, our findings further support the role of DHA as a suitable anticarcinogenic factor against nonmelanoma skin cancers.

Characterization of the S-denitrosylating activity of bilirubin

Bilirubin-IX-alpha (BR) is an endogenous molecule with a strong antioxidant feature due to its ability to scavenge free radicals. In this paper, we demonstrated that BR, at concentrations close to those found within the cell (0.1-2.5 microM), acted as a denitrosylating agent and increased the release of nitric oxide from S-nitrosoglutathione (GSNO) and S-nitrosocysteine (SNOC) (2.5 microM). The complexation of BR with saturating concentrations of human serum albumin (HSA, 2.5 microM) did not further increase nitric oxide release from GSNO and SNOC. At concentrations similar to those reached in plasma (5-20 microM), BR denitrosylated S-nitroso-HSA (2.5 microM), the main circulating S-nitrosothiol, and this effect was potentiated by the complexation of BR with saturating HSA (20 microM). Furthermore, the product(s) of the reaction between nitric oxide and BR were identified. Ultraviolet and mass spectrometry analysis revealed that nitric oxide binds to BR forming a N-nitroso derivative (BR-nitric oxide) with extinction coefficients of 1.393 mM(-1)cm(-1) and 2.254 mM(-1)cm(-1) in methanol and NaOH, respectively. The formation of BR-nitric oxide did not occur only in a reconstituted system, but was confirmed in rat fibroblasts exposed to pro-oxidant stimuli. These results provided novel insights on the antioxidant characteristic of BR through its interaction with nitric oxide, a gaseous neurotransmitter with a well-known dual effect, namely neuroprotective under physiological conditions or neurotoxic if produced in excess, and proposed BR-nitric oxide as a new biomarker of oxidative/nitrosative stress.