"Click" on PLGA-PEG and hyaluronic acid: Gaining access to anti-leishmanial pentamidine bioconjugates

Repurposing the anti-parasitic agent pentamidine for cancer therapy; a novel approach with promising anti-tumor properties

Pentamidine (PTM) is an aromatic diamidine administered for infectious diseases, e.g. sleeping sickness, malaria, and Pneumocystis jirovecii pneumonia. Due to similarities of cellular mechanisms between human cells and such infections, PTM has also been proposed for repurposing in non-infectious diseases such as cancer. Indeed, by modulating different signaling pathways such as PI3K/AKT, MAPK/ERK, p53, PD-1/PD-L1, etc., PTM has been shown to inhibit different properties of cancer, including proliferation, invasion, migration, hypoxia, and angiogenesis, while inducing anti-tumor immune responses and apoptosis. Given the promising implications of PTM for cancer treatment, however, the clinical translation of PTM in cancer is not without certain challenges. In fact, clinical trials have shown that systemic administration of PTM can be concurrent with serious adverse effects, e.g. hypoglycemia. Therefore, to reduce the administered doses of PTM, lower the risk of adverse effects, and prevent any potential drug resistance, while maintaining the anti-tumor efficacy, two main strategies have been suggested. One is combination therapy that employs PTM in conjunction with other anti-cancer modalities, such as chemotherapy and radiotherapy, and attacks tumor cells with significant additive or synergistic anti-tumor effects. The other is developing PTM-loaded nanocarrier drug delivery systems e.g. pegylated liposomes, chitosan-coated niosomes, squalene-based nanoparticles, hyaluronated lipid-polymer hybrid nanoparticles, etc., that offer enhanced pharmacokinetic characteristics, including increased bioavailability, sit-targeting, and controlled/sustained drug release. This review highlights the anti-tumor properties of PTM that favor its repurposing for cancer treatment, as well as, PTM-based combination therapies and nanocarrier delivery systems which can enhance therapeutic efficacy and simultaneously reduce toxicity.

RGD-tagging of star-shaped PLA-PEG micellar nanoassemblies enhances doxorubicin efficacy against osteosarcoma

We developed cyclic RGD-tagged polymeric micellar nanoassemblies for sustained delivery of Doxorubicin (Dox) endowed with significant cytotoxic effect against MG63, SAOS-2, and U2-OS osteosarcoma cells without compromising the viability of healthy osteoblasts (hFOBs). Targeted polymeric micellar nanoassemblies (RGD-NanoStar@Dox) enabled Dox to reach the nucleus of MG63, SAOS-2, and U2-OS cells causing the same cytotoxic effect as free Dox, unlike untargeted micellar nanoassemblies (NanoStar@Dox) which failed to reach the nucleus and resulted ineffective, demonstrating the crucial role of cyclic RGD peptide in driving cellular uptake and accumulation mechanisms in osteosarcoma cells. Micellar nanoassemblies were obtained by nanoformulation of three-armed star PLA-PEG copolymers properly synthetized with and without decoration with the cyclic-RGDyK peptide (Arg-Gly-Asp-D-Tyr-Lys). The optimal RGD-NanoStar@Dox nanoformulation obtained by nanoprecipitation method (8 % drug loading; 35 % encapsulation efficiency) provided a prolonged and sustained drug release with a rate significantly lower than the free drug under the same experimental conditions. Moreover, the nanosystem preserved Dox from the natural degradation occurring under physiological conditions (i.e., dimerization and consequent precipitation) serving as a slow-release "drug reservoir" ensuring an extended biological activity over the time.

PLGA Nanoparticles as New Drug Delivery Systems in Leishmaniasis Chemotherapy: A Review of Current Practices

Although leishmaniasis is one of the most common parasitic diseases, its traditional treatments suffer from some serious problems. To solve such issues, we can take advantage of the effective nanoparticle-based approaches to deliver anti-leishmanial agents into leishmania-infected macrophages either using passive targeting or using macrophagerelated receptors. Despite the high potential of nanotechnology, Liposomal Amphotericin B (AmBisome®) is the only FDA-approved nanoparticle-based anti-leishmanial therapy. In an effort to find more anti-leishmanial nano-drugs, this 2011-2021 review study aimed to investigate the in-vivo and in-vitro effectiveness of poly (lactic-co-glycolic acid) nanoparticles (PLGA-NPs) in the delivery of some traditional anti-leishmanial drugs. Based on the results, PLGA-NPs could improve solubility, controlled release, trapping efficacy, bioavailability, selectivity, and mucosal penetration of the drugs, while they decreased resistance, dose/duration of administration and organotoxicity of the agents. However, none of these nano-formulations have been able to enter clinical trials so far. We summarized the data about the common problems of anti-leishmanial agents and the positive effects of various PLGA nano-formulations on reducing these drawbacks under both in-vitro and in-vivo conditions in three separate tables. Overall, this study proposes two AmB-loaded PLGA with a 99% reduction in parasite load as promising nanoparticles for further studies.

Portable NIR spectroscopy: the route to green analytical chemistry

There is a growing interest for cost-effective and nondestructive analytical techniques in both research and application fields. The growing approach by near-infrared spectroscopy (NIRs) pushes to develop handheld devices devoted to be easily applied for in situ determinations. Consequently, portable NIR spectrometers actually result definitively recognized as powerful instruments, able to perform nondestructive, online, or in situ analyses, and useful tools characterized by increasingly smaller size, lower cost, higher robustness, easy-to-use by operator, portable and with ergonomic profile. Chemometrics play a fundamental role to obtain useful and meaningful results from NIR spectra. In this review, portable NIRs applications, published in the period 2019-2022, have been selected to indicate starting references. These publications have been chosen among the many examples of the most recent applications to demonstrate the potential of this analytical approach which, not having the need for extraction processes or any other pre-treatment of the sample under examination, can be considered the "true green analytical chemistry" which allows the analysis where the sample to be characterized is located. In the case of industrial processes or plant or animal samples, it is even possible to follow the variation or evolution of fundamental parameters over time. Publications of specific applications in this field continuously appear in the literature, often in unfamiliar journal or in dedicated special issues. This review aims to give starting references, sometimes not easy to be found.

Harnessing the power of PLA-PEG Nanoparticles for Linezolid delivery against Methicillin-Resistant Staphylococcus aureus

This study deals with the development of novel poly(lactic acid-co-polyethylene glycol) nanoparticles (PLA-PEG NPs) for the efficient and prolonged delivery of Linezolid (LNZ), a synthetic antibacterial agent used against methicillin-resistant Staphylococcus aureus (MRSA). A two-step synthetic strategy based on carbodiimide coupling and copper-catalyzed azide-alkyne cycloaddition was first exploited for the conjugation of PLA with PEG. The encapsulation of LNZ into medium-molecular-weight PLA-PEG NPs was carried out by different methods including nanoprecipitation and dialysis. The optimal PLA-PEG@LNZ nanoformulation resulted in 3.5% LNZ payload (15% encapsulation efficiency, with a 10:3 polymer to drug ratio) and sustained release kinetics with 65% of entrapped antibiotic released within 80 h. Moreover, the zeta potential values (from -31 to -39 mV) indicated a good stability without agglomeration even after freeze-drying and lyophilization. The PLA-PEG@LNZ NPs exerted antimicrobial activity against a panel of Gram-positive bacteria responsible for human infections, such as S. aureus, MRSA, S. epidermidis, S. lugdunensis and vancomycin resistant Enterococcus faecium (VRE). Moreover, PLA-PEG@LNZ NPs showed inhibitory activity on both planktonic growth and preformed biofilm of MRSA. The antibacterial activity of LNZ incorporated in polymeric NPs was well preserved and the nanosystem served as an antibiotic enhancer with a potential role in MRSA-associated infections management.

Microencapsulation by a Spray Drying Approach to Produce Innovative Probiotics-Based Products Extending the Shelf-Life in Non-Refrigerated Conditions

Recently, there has been a growing interest in producing functional foods containing encapsulated probiotic bacteria due to their positive effects on human health. According to their perceived health benefits, probiotics have been incorporated into a range of dairy products, but the current major challenge is to market new, multicomponent probiotic foods and supplements. Nevertheless, only a few products containing encapsulated probiotic cells can be found as non-refrigerated products. In this work, spray drying technology was investigated in order to produce an innovative nutraceutical formulation based on lactic acid bacteria (LAB), and was able to ensure a good storage stability of probiotics (no less than 109 CFU/cps) in non-refrigerated conditions. Probiotic-loaded microparticles from spray drying experiments were produced under different conditions and compared by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and the enumeration of the number of viable cells in order to identify the formulation exhibiting the most promising characteristics. Results from the dissolution test revealed that the optimized formulation provides a suitable amount of living cells after digestion of microparticles stored for 12 months at room temperature and confirmed that the microencapsulation process by spray drying ensures a good protection of probiotics for nutraceutical purposes.

On-Line Thermally Induced Evolved Gas Analysis: An Update-Part 2: EGA-FTIR

The on-line thermally induced evolved gas analysis (OLTI-EGA) is widely applied in many different fields. Aimed to update the applications, our group has systematically collected and published examples of EGA characterizations. Following the recently published review on EGA-MS applications, this second part reviews the latest applications of Evolved Gas Analysis performed by on-line coupling heating devices to infrared spectrometers (EGA-FTIR). The selected 2019, 2020, 2021 and early 2022 references are collected and briefly described in this review; these are useful to help researchers to easily find applications that are sometimes difficult to locate.

Supramolecular assembly of pentamidine and polymeric cyclodextrin bimetallic core-shell nanoarchitectures

Advanced nanoscale antimicrobials, originated from the combination of noble metal nanoparticles (NPs) with conventional antimicrobial drugs, are considered the next generation of antimicrobial agents. Therefore, there is an increasing demand for rapid, eco-friendly, and relatively inexpensive synthetic approaches for the preparation of nontoxic metallic nanostructures endowed with unique physicochemical properties. Recently, we have proposed a straightforward synthetic strategy that exploits the properties of polymeric β-cyclodextrin (PolyCD) to act as both the reducing and stabilizing agent to produce monodispersed and stable gold-based NPs either as monometallic (nanoG) structures or core-shell bimetallic (nanoGS) architectures with an external silver layer. Here, we describe the preparation of a supramolecular assembly between nanoGS and pentamidine, an antileishmanial drug endowed with a wide range of therapeutic properties (i.e., antimicrobial, anti-inflammatory, and anticancer). The physicochemical characterization of the supramolecular assembly (nanoGSP) in terms of size and colloidal stability was investigated by complementary spectroscopic techniques, such as UV-vis, ζ-potential, and dynamic light scattering (DLS). Furthermore, the role of PolyCD during the reduction/stabilization of metal NPs was investigated for the first time by NMR spectroscopy.

A Multifunctional Conjugated Polymer Developed as an Efficient System for Differentiation of SH-SY5Y Tumour Cells

Polymer-based systems have been demonstrated in novel therapeutic and diagnostic (theranostic) treatments for cancer and other diseases. Polymers provide a useful scaffold to develop multifunctional nanosystems that combine various beneficial properties such as drug delivery, bioavailability, and photosensitivity. For example, to provide passive tumour targeting of small drug molecules, polymers have been used to modify and functionalise the surface of water-insoluble drugs. This approach also allows the reduction of adverse side effects, such as retinoids. However, multifunctional polymer conjugates containing several moieties with distinct features have not been investigated in depth. This report describes the development of a one-pot approach to produce a novel multifunctional polymer conjugate. As a proof of concept, we synthesised polyvinyl alcohol (PVA) covalently conjugated with rhodamine B (a tracking agent), folic acid (a targeting agent), and all-trans retinoic acid (ATRA, a drug). The obtained polymer (PVA@RhodFR) was characterised by MALDI-TOF mass spectrometry, gel permeation chromatography, thermal analysis, dynamic light-scattering, NMR, UV-Vis, and fluorescence spectroscopy. Finally, to evaluate the efficiency of the multifunctional polymer conjugate, cellular differentiation treatments were performed on the neuroblastoma SH-SY5Y cell line. In comparison with standard ATRA-based conditions used to promote cell differentiation, the results revealed the high capability of the new PVA@RhodFR to induce neuroblastoma cells differentiation, even with a short incubation time and low ATRA concentration.

Three-armed RGD-decorated starPLA-PEG nanoshuttle for docetaxel delivery

A novel star-shaped amphiphilic copolymer based on three poly(lactide)-block-poly(ethylene glycol) (PLA-PEG) terminal arms extending from a glycerol multifunctional core was newly synthesized and decorated with the tumor-targeting ligand cyclic-RGDyK peptide (Arg-Gly-Asp-D-Tyr-Lys) to be eventually formulated in polymeric micelles incorporating a suitable anticancer drug (i.e., Docetaxel, DTX; drug loading 16 %, encapsulation efficiency 69 %). The biological profile of unloaded micelles (RGD-NanoStar) was studied on Human Adipose-derived Mesenchymal Stem Cells (Ad-MSCs) as health control, pointing out the absence of toxicity. Surprisingly, an unprecedented effect on cell viability was exerted by RGD-NanoStar, comparable to that of the free DTX, on tumoral MDA-MB 468 Human Breast Adenocarcinoma cells, specifically starting from 48 h of culture (about 40 % and 60 % of dead cells at 48 and 72 h, respectively, at all tested concentrations). RGD-NanoStar reduced the cell viability also of tumoral U87 Human Glioblastoma cells, compared to cells only, at 72 h (about 25 % of dead cells) demonstrating a time-dependent effect exerted by the highest concentrations. The effects of DTX-loaded micelles (RGD-NanoStar/DTX) on U87 and MDA-MB 468 cell lines were evaluated by MTT, cell morphology analysis, and scratch test. A compromised cell morphology was observed without significant difference between DTX-treated and RGD-NanoStar/DTX - treated cells, especially in U87 cell line. Although no apparent benefit emerged from the drug incorporation into the nanosystem by MTT assay, the scratch test revealed a statistically significant inhibition of tumoral cell migration on both cell lines, confirming the well-known role of DTX in inhibiting cell movements even when loaded on polymeric micelles. Specifically, only 43 μm distance was covered by U87 cells after 30 h culture with RGD-NanoStar/DTX (30 μg/mL) compared to 73 μm in the presence of free DTX at the same concentration; more interestingly, a total absence of MDA-MB 468 cell movements was detected at 30 h compared to about 50 μm distance covered by cells in the presence of free DTX (10 μg/mL). The stronger inhibitory activity on cell migration of RGD-NanoStar/DTX compared to the free drug in both cell lines at 30 h attested for a good ability of the drug-loaded nanocarrier to reduce tumor propagation and invasiveness, enhancing the typical effect of DTX on metastatization.

On-Line Thermally Induced Evolved Gas Analysis: An Update-Part 1: EGA-MS

Advances in on-line thermally induced evolved gas analysis (OLTI-EGA) have been systematically reported by our group to update their applications in several different fields and to provide useful starting references. The importance of an accurate interpretation of the thermally-induced reaction mechanism which involves the formation of gaseous species is necessary to obtain the characterization of the evolved products. In this review, applications of Evolved Gas Analysis (EGA) performed by on-line coupling heating devices to mass spectrometry (EGA-MS), are reported. Reported references clearly demonstrate that the characterization of the nature of volatile products released by a substance subjected to a controlled temperature program allows us to prove a supposed reaction or composition, either under isothermal or under heating conditions. Selected 2019, 2020, and 2021 references are collected and briefly described in this review.

Pentamidine Ninety Years on: the Development and Applications of Pentamidine and its Analogs

Pentamidine, an FDA-approved human drug for many protozoal infections, was initially synthesized in the late 1930s and first reported to be curative for parasitosis in the 1940s. After ninety years of sometimes quiet growth, pentamidine and its derivatives have gone far beyond antibacterial agents, including but not limited to the ligands of DNA minor groove, modulators of PPIs (protein-protein interactions) of the transmembrane domain 5 of lateral membrane protein 1, and the blockers of the SARS-CoV-2 3a channel. This mini review highlights the development and applications of pentamidine and its analogs, aiming to provide insights for further developing pentamidine derivatives in the following decades.

Nanotechnological approaches for pentamidine delivery

Pentamidine (PTM), which is a diamine that is widely known for its antimicrobial activity, is a very interesting drug whose mechanism of action is not fully understood. In recent years, PTM has been proposed as a novel potential drug candidate for the treatment of mental illnesses, myotonic dystrophy, diabetes, and tumors. Nevertheless, the systemic administration of PTM causes severe side effects, especially nephrotoxicity. In order to efficiently deliver PTM and reduce its side effects, several nanosystems that take advantage of the chemical characteristics of PTM, such as the presence of two positively charged amidine groups at physiological pH, have been proposed as useful delivery tools. Polymeric, lipidic, inorganic, and other types of nanocarriers have been reported in the literature for PTM delivery, and they are all in different development phases. The available approaches for the design of PTM nanoparticulate delivery systems are reported in this review, with a particular emphasis on formulation strategies and in vitro/in vivo applications. Furthermore, a critical view of the future developments of nanomedicine for PTM applications, based on recent repurposing studies, is provided. Created with BioRender.com.

Recent Advances and Challenges in Gene Delivery Mediated by Polyester-Based Nanoparticles

Gene therapy is a promising approach for the treatment of several diseases, such as chronic or viral infections, inherited disorders, and cancer. The cellular internalization of exogenous nucleic acids (NA) requires efficient delivery vehicles to overcome their inherent pharmacokinetic drawbacks, e.g. electrostatic repulsions, enzymatic degradation, limited cellular uptake, fast clearance, etc. Nanotechnological advancements have enabled the use of polymer-based nanostructured biomaterials as safe and effective gene delivery systems, in addition to viral vector delivery methods. Among the plethora of polymeric nanoparticles (NPs), this review will provide a comprehensive and in-depth summary of the polyester-based nanovehicles, including poly(lactic-co-glycolic acid) (PLGA) and polylactic acid (PLA) NPs, used to deliver a variety of foreign NA, e.g. short interfering RNA (siRNA), messenger RNA (mRNA), and plasmid DNA (pDNA). The article will review the versatility of polyester-based nanocarriers including their recent application in the delivery of the clustered, regularly-interspaced, short palindromic repeats/Cas (CRISPR/Cas) genome editing system for treating gene-related diseases. The remaining challenges and future trend of the targeted delivery of this revolutionary genome-editing system will be discussed. Special attention will be given to the pivotal role of nanotechnology in tackling emerging infections such as coronavirus disease 2019 (COVID-19): ground-breaking mRNA vaccines delivered by NPs are currently used worldwide to fight the pandemic, pushing the boundaries of gene therapy.

Oxazolidinone Antibiotics: Chemical, Biological and Analytical Aspects

This review covers the main aspects concerning the chemistry, the biological activity and the analytical determination of oxazolidinones, the only new class of synthetic antibiotics advanced in clinical use over the past 50 years. They are characterized by a chemical structure including the oxazolidone ring with the S configuration of substituent at C5, the acylaminomethyl group linked to C5 and the N-aryl substituent. The synthesis of oxazolidinones has gained increasing interest due to their unique mechanism of action that assures high antibiotic efficiency and low susceptibility to resistance mechanisms. Here, the main features of oxazolidinone antibiotics licensed or under development, such as Linezolid, Sutezolid, Eperezolid, Radezolid, Contezolid, Posizolid, Tedizolid, Delpazolid and TBI-223, are discussed. As they are protein synthesis inhibitors active against a wide spectrum of multidrug-resistant Gram-positive bacteria, their biological activity is carefully analyzed, together with the drug delivery systems recently developed to overcome the poor oxazolidinone water solubility. Finally, the most employed analytical techniques for oxazolidinone determination in different matrices, such as biological fluids, tissues, drugs and natural waters, are reviewed. Most are based on HPLC (High Performance Liquid Chromatography) coupled with UV-Vis or mass spectrometer detectors, but, to a lesser extent are also based on spectrofluorimetry or voltammetry.

Cu(I)-Catalyzed Click Chemistry in Glycoscience and Their Diverse Applications

Copper(I)-catalyzed 1,3-dipolar cycloaddition between organic azides and terminal alkynes, commonly known as CuAAC or click chemistry, has been identified as one of the most successful, versatile, reliable, and modular strategies for the rapid and regioselective construction of 1,4-disubstituted 1,2,3-triazoles as diversely functionalized molecules. Carbohydrates, an integral part of living cells, have several fascinating features, including their structural diversity, biocompatibility, bioavailability, hydrophilicity, and superior ADME properties with minimal toxicity, which support increased demand to explore them as versatile scaffolds for easy access to diverse glycohybrids and well-defined glycoconjugates for complete chemical, biochemical, and pharmacological investigations. This review highlights the successful development of CuAAC or click chemistry in emerging areas of glycoscience, including the synthesis of triazole appended carbohydrate-containing molecular architectures (mainly glycohybrids, glycoconjugates, glycopolymers, glycopeptides, glycoproteins, glycolipids, glycoclusters, and glycodendrimers through regioselective triazole forming modular and bio-orthogonal coupling protocols). It discusses the widespread applications of these glycoproducts as enzyme inhibitors in drug discovery and development, sensing, gelation, chelation, glycosylation, and catalysis. This review also covers the impact of click chemistry and provides future perspectives on its role in various emerging disciplines of science and technology.

Recent advancements in anti-leishmanial research: Synthetic strategies and structural activity relationships

Leishmaniasis is a parasitic neglected tropical disease caused by various species of Leishmania parasite. Despite tremendous advancements in the therapeutic sector and drug development strategies, still the existing anti-leishmanial agents are associated with some clinical issues like drug resistance, toxicity and selectivity. Therefore, several research groups are continuously working towards the development of new therapeutic candidates to overcome these issues. Many potential heterocyclic moieties have been explored for this purpose including triazoles, chalcones, chromone, thiazoles, thiosemicarbazones, indole, quinolines, etc. It is evident from the literature that the majority of anti-leishmanial agents act by interacting with key regulators including PTR-I, DHFR, LdMetAP1, MAPK, 14 α-demethylase and pteridine reductase-I, etc. Also, these tend to induce the production of ROS which causes damage to parasites. In the present compilation, authors have summarized various significant synthetic procedures for anti-leishmanial agents reported in recent years. A brief description of the pharmacological potentials of synthesized compounds along with important aspects related to structural activity relationship has been provided. Important docking outcomes highlighting the possible mode of interaction for the reported compounds have also been included. This review would be helpful to the scientific community to design newer strategies and also to develop novel therapeutic candidates against leishmaniasis.

Nanotechnology-aided diagnosis, treatment and prevention of leishmaniasis

Leishmaniasis is a prevalent parasitic infection belonging to neglected tropical diseases. It is caused by Leishmania protozoan parasites transmitted by sandflies and it is responsible for increased morbidity/mortality especially in low- and middle-income countries. The lack of cheap, portable, easy to use diagnostic tools exhibiting high efficiency and specificity impede the early diagnosis of the disease. Furthermore, the typical anti-leishmanial agents are cytotoxic, characterized by low patient compliance and require long-term regimen and usually hospitalization. In addition, due to the intracellular nature of the disease, the existing treatments exhibit low bioavailability resulting in low therapeutic efficacy. The above, combined with the common development of resistance against the anti-leishmanial agents, denote the urgent need for novel therapeutic strategies. Furthermore, the lack of effective prophylactic vaccines hinders the control of the disease. The development of nanoparticle-based biosensors and nanocarrier-aided treatment and vaccination strategies could advance the diagnosis, therapy and prevention of leishmaniasis. The present review intends to highlight the various nanotechnology-based approaches pursued until now to improve the detection of Leishmania species in biological samples, decrease the side effects and increase the efficacy of anti-leishmanial drugs, and induce enhanced immune responses, specifically focusing on the outcome of their preclinical and clinical evaluation.

Zoledronic Acid-Loaded Hybrid Hyaluronic Acid/Polyethylene Glycol/Nano-Hydroxyapatite Nanoparticle: Novel Fabrication and Safety Verification

Osteosarcoma is a malignant tumor that often occurs in adolescents and children. Zoledronic acid, a new-generation bisphosphonate, has been widely used as an antitumor drug to inhibit bone metastasis. However, the rapid renal elimination results in low effective concentrations. Meanwhile, high-dose intravenous zoledronic acid administration leads to severe side effects. The present study fabricated an organic-inorganic hybrid nanoparticle as the carrier of zoledronic acid. The rod-like nanoparticle, which had 150-nm length and 40-nm cross-sectional diameter, consisted of a hyaluronic acid/polyethylene glycol (HA-PEG) polymer shell and a nano-hydroxyapatite (nHA) core, with zoledronic acid molecules loading on the surface of nHA and clearance of HA-PEG shell. The nanoparticle was characterized by microscopic analysis, in vitro release study, cytotoxicity analysis, and in vivo immune response examination. Results showed that the compact and stable structure could achieve high drug loading efficiency, sustained drug release, and great biocompatibility. In vitro and in vivo experiments revealed the low cytotoxicity and acceptable immune response under low-dose nanoparticle treatment, indicating its potential application for future osteosarcoma therapeutic strategies.

Design of naturally inspired jellyfish-shaped cyclopolylactides to manage osteosarcoma cancer stem cells fate

We report the synthesis, characterization and biological profile of new bis-triazoled cyclopolylactides (c-PLA, c-PLA-FA, c-PLA-Rhod) obtained by an optimized combination of ROP and click chemistry reactions. Cyclo-PLA having a number average molecular weight of 6000 g mol^-1 and a polydispersity index of 1.52 was synthetized by click ring-closure of well-defined α,ω-heterodifunctional linear precursors, followed by quaternarization of N₃-triazole nodes, and subsequent CuAAC with azido-folate and azido-rhodamine yielding jellyfish-shaped c-PLA-FA and c-PLA-Rhod. Salinomycin (Sal) was loaded into jellyfish-shaped c-PLA-FA and c-PLA-Rhod nanoparticles (NPs) by nanoprecipitation, with a good encapsulation efficiency (79% and 84%, respectively) and loading content (7.1% and 7.6%, respectively). The biological studies focused on their antiproliferative effects on osteosarcoma bulk MG63 and cancer stem cells (CSCs). The cycloPLA-based NPs, with a size ranging between 125 and 385 nm, killed CSCs and MG63, with a higher efficacy on CSCs; they (unloaded or Sal-loaded) evoked on CSCs a cellular response similar to the payload, with a higher effect than the free Sal. Internalization studies indicated a fast cellular uptake (within 2 h) and sarcospheres remained fluorescent till 72 h. To the best of our knowledge, this is the first study reporting anti-CSCs properties of cycloPLA with jellyfish architecture and we believe could contribute to the development of effective strategies for osteosarcoma targeting.

Pentamidine-Loaded Lipid and Polymer Nanocarriers as Tunable Anticancer Drug Delivery Systems

Initially developed as a synthetic analogue of insulin, pentamidine (PTM) is an antimicrobial drug that has recently shown in vitro and in vivo anticancer activity. Nevertheless, systemic administration of PTM causes severe side effects, especially nephrotoxicity. Here we propose the association of PTM to different biocompatible nanosystems in order to compare the physicochemical characteristics of the loaded nanocarriers and their influence on the drug cytotoxicity toward cancer cells. In particular, PTM (as free base or with different counterions) was encapsulated into liposomes and poly(lactide-co-glycolide) (PLGA) nanoparticles and all the formulations have been deeply characterized concerning mean diameter, polydispersity index, zeta potential, stability, morphology, PTM loading, and drug release profile. The anticancer activity was evaluated on a human ovarian cancer cell line over 72 h. Results showed that PTM is efficiently loaded into liposomes with a transmembrane citrate or sulfate gradient; concerning PLGA nanoparticles, important association occurred, thanks to ionic interactions between the drug and the polymer. The in vitro studies confirmed the anticancer activity of PTM, which was gradually released with different profiles depending on the drug form and the nanocarrier structure.

Oral pentamidine-loaded poly(d,l-lactic-co-glycolic) acid nanoparticles: an alternative approach for leishmaniasis treatment

Leishmaniasis is a group of diseases caused by a protozoa parasite from one of over 20 Leishmania species. Depending on the tissues infected, these diseases are classified as cutaneous, mucocutaneous and visceral leishmaniasis. For the treatment of leishmaniasis refractory to antimony-based drugs, pentamidine (PTM) is a molecule of great interest. However, PTM displays poor bioavailability through oral routes due to its two strongly basic amidine moieties, which restricts its administration by a parenteral route and limits its clinical use. Among various approaches, nanotechnology-based drug delivery systems (nano-DDS) have potential to overcome the challenges associated with PTM oral administration. Here, we present the development of PTM-loaded PLGA nanoparticles (NPs) with a focus on the characterization of their physicochemical properties and potential application as an oral treatment of leishmaniasis. NPs were prepared by a double emulsion methodology. The physicochemical properties were characterized through the mean particle size, polydispersity index (PdI), zeta potential, entrapment efficiency, yield process, drug loading, morphology, in vitro drug release and in vivo pharmacological activity. The PTM-loaded PLGA NPs presented with a size of 263 ± 5 nm (PdI = 0.17 ± 0.02), an almost neutral charge (-3.2 ± 0.8 mV) and an efficiency for PTM entrapment of 91.5%. The release profile, based on PTM dissolution, could be best described by a zero-order model, followed by a drug diffusion profile that fit to the Higuchi model. In addition, in vivo assay showed the efficacy of orally given PTM-loaded PLGA NPs (0.4 mg kg^-1) in infected BALB/c mice, with significant reduction of organ weight and parasite load in spleen (p-value < 0.05). This work successfully reported the oral use of PTM-loaded NPs, with a high potential for the treatment of visceral leishmaniasis, opening a new perspective to utilization of this drug in clinical practice.

Innovative Solutions for the Control of Leishmaniases: Nanoscale Drug Delivery Systems

Background:

Leishmania are sandfly-transmitted protozoan parasites that harbour within the macrophages of a mammalian host and cause leishmaniasis, a serious zoonotic disease that threatens the lives of millions worldwide. Its numerous forms (cutaneous, mucocutaneous, and visceral) are currently treated with a sparse arsenal of drugs, specifically antimonials, amphotericin B, miltefosine, and paromomycin, for which drug resistance and clinical failure are rampant. Medicine is presently trending towards nanotechnology to aid in the successful delivery of drugs. Vehicles such as lipid-based nanocarriers, polymer-based nanoparticles, and metal ions and oxides have been previously demonstrated to improve bioavailability of drugs and decrease toxicity for the patient. These cutting-edge solutions can be combined with existing active molecules, as well as novel drugs or plant extracts with promising antileishmanial activity.

Conclusion:

This review explores the current evidence for the treatment of leishmaniases using nanoscale drug delivery systems (specifically lipid-, polymer- and metal-based systems) and encourages further development of the aforementioned nanotechnologies for treatment of Leishmania.

Strategies to Obtain Encapsulation and Controlled Release of Pentamidine in Mesoporous Silica Nanoparticles

Pentamidine (PTM), an antiprotozoal agent used in clinics as pentamidine isethionate salt (PTM-S), recently showed high potential also for the treatment of cancer and myotonic dystrophy type I. However, a severe limit to the systemic administration of PTM is represented by its nephrotoxicity, leading to the need for a system able to achieve a controlled release of the drug. In this study, mesoporous silica nanoparticles (MSNs) were employed for the first time to encapsulate PTM. PTM-S was first used for loading experiments into bare (MSN-OH) and aminopropyl, cyanopropyl and carboxypropyl-functionalized MSNs (MSN-NH₂, MSN-CN and MSN-COOH respectively) but it was not adequately loaded in any MSNs. The free base of PTM (PTM-B) was then obtained from PTM-S and successfully loaded into MSNs. Specifically, MSN-COOH exhibited the highest loading capacity. In vitro evaluation of PTM-B kinetic release from the different MSNs was carried out. An influence of the functional groups in slowing the release of the drug, when compared to bare MSNs was observed. Altogether, these results demonstrate that MSN-COOH could be a promising system to achieve a controlled release of PTM.