PLA-PEG nanocapsules radiolabeled with 99mTechnetium-HMPAO: Release properties and physicochemical characterization by atomic force microscopy and photon correlation spectroscopy

Triple-layered platform utilizing electrospun nanofibers and 3D-printed sodium alginate-based hydrogel for effective topical treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), an autoimmune disease impacting the joints, significantly diminishes the quality of life for patients. Conventional treatments predominantly rely on oral or injectable formulations, underscoring the crucial need for an effective topical remedy. The present study reports a novel triple-layered transdermal platform for efficient RA treatment. The patches are based on an electrospun/electrosprayed diclofenac (DIC)-conjugated polyvinyl alcohol (PVA) nanofibers/nanoparticles (NFs/NPs) composite layer sandwiched between an electrospun supporting layer of polycaprolactone (PCL) NFs, and a 3D-printed sodium alginate-based hydrogel (HG) layer incorporating sodium hyaluronate (HA) and rosuvastatin (ROS)-loaded core-shell lipid nanocapsules (LNCs). The ingeniously designed transdermal patches release the chemically conjugated DIC via skin-secreted esterases at the inflamed sites. The LNCs and patches were characterized using DLS, FTIR, DSC, and electron microscopy. ROS-loaded LNCs (<50 nm as per the TEM micrographs) were able to release about 97 % of ROS during 5 days. In-vitro and in-vivo evaluations definitively established the efficacy of the developed platform, showcasing a substantial reduction in IL-6 and TNF-α through sandwich ELISA measurements in cell culture and Rattus norvegicus plasma samples. Besides, the stained photomicrographs of the rats' ankle joints confirmed the alleviation of the RA symptoms via reducing cell infiltration with a preserved joint tissue structure.

Nanoparticles labeled with gamma-emitting radioisotopes: an attractive approach for in vivo tracking using SPECT imaging

Providing accurate molecular imaging of the body and biological process is critical for diagnosing disease and personalizing treatment with the minimum side effects. Recently, diagnostic radiopharmaceuticals have gained more attention in precise molecular imaging due to their high sensitivity and appropriate tissue penetration depth. The fate of these radiopharmaceuticals throughout the body can be traced using nuclear imaging systems, including single-photon emission computed tomography (SPECT) and positron emission tomography (PET) modalities. In this regard, nanoparticles are attractive platforms for delivering radionuclides into targets because they can directly interfere with the cell membranes and subcellular organelles. Moreover, applying radiolabeled nanomaterials can decrease their toxicity concerns because radiopharmaceuticals are usually administrated at low doses. Therefore, incorporating gamma-emitting radionuclides into nanomaterials can provide imaging probes with valuable additional properties compared to the other carriers. Herein, we aim to review (1) the gamma-emitting radionuclides used for labeling different nanomaterials, (2) the approaches and conditions adopted for their radiolabeling, and (3) their application. This study can help researchers to compare different radiolabeling methods in terms of stability and efficiency and choose the best way for each nanosystem.

PEGylated and functionalized polylactide-based nanocapsules: An overview

Polymeric nanocapsules (NC) are versatile mixed vesicular nanocarriers, generally containing a lipid core with a polymeric wall. They have been first developed over four decades ago with outstanding applicability in the cosmetic and pharmaceutical fields. Biodegradable polyesters are frequently used in nanocapsule preparation and among them, polylactic acid (PLA) derivatives and copolymers, such as PLGA and amphiphilic block copolymers, are widely used and considered safe for different administration routes. PLA functionalization strategies have been developed to obtain more versatile polymers and to allow the conjugation with bioactive ligands for cell-targeted NC. This review intends to provide steps in the evolution of NC since its first report and the recent literature on PLA-based NC applications. PLA-based polymer synthesis and surface modifications are included, as well as the use of NC as a novel tool for combined treatment, diagnostics, and imaging in one delivery system. Furthermore, the use of NC to carry therapeutic and/or imaging agents for different diseases, mainly cancer, inflammation, and infections is presented and reviewed. Constraints that impair translation to the clinic are discussed to provide safe and reproducible PLA-based nanocapsules on the market. We reviewed the entire period in the literature where the term "nanocapsules" appears for the first time until the present day, selecting original scientific publications and the most relevant patent literature related to PLA-based NC. We presented to readers a historical overview of these Sui generis nanostructures.

Intranasally administered melatonin core-shell polymeric nanocapsules: A promising treatment modality for cerebral ischemia

AIMS

The neurohormone melatonin (MEL) has been reported as a promising neuroprotective molecule, however it suffers pharmaceutical limitations such as poor solubility and low bioavailability, which hinder its pharmacological and clinical potential. In the current work, MEL was loaded in core-shell nanocarrier system; polymeric nanocapsules (PNCs), and assessed for its potential in cerebral ischemia reperfusion injury rat model when administered intranasally.

KEY FINDINGS

Adopting a D-optimal factorial design, MEL-PNCs were successfully formulated using the nanoprecipitation technique. MEL-PNCs exhibited a particle size ranging from 143.5 to 444 nm, negative zeta potential values ranging from -24.2 to -38.7 mV, cumulative release % for MEL ranging from 36.79 to 41.31 % over 8 h period, with overall good storage properties. The selected MEL-PNCs formulation displayed 8-fold higher permeation than the drug solution across sheep nasal mucosa. MEL-PNCs administered intranasally decreased oxidative stress and hippocampal inflammation, and the histological examination revealed the significant restoration of hippocampal neurons.

SIGNIFICANCE

MEL-PNCs administered intranasally could be a promising treatment modality in brain ischemia.

Emerging uses of PLA-PEG copolymer in cancer drug delivery

Traditional therapies need high systematic dosages that not only destroys cancerous cells but also healthy cells. To overcome this problem recent advancement in nanotechnology specifically in nanomaterials has been extensively done for various biological applications, such as targeted drug delivery. Nanotechnology, as a frontier science, has the potential to break down all the obstacles to be more effective and secure drug delivery system. It is possible to develop nanopolymer based drug carrier that can target drugs with extreme accuracy. Polymers can advance drug delivery technologies by allowing controlled release of therapeutic drugs in stable amounts over long duration of time. For controlled drug delivery, biodegradable synthetic polymers have various benefits over non-biodegradable polymers. Biodegradable polymer either are less toxic or non-toxic. Polylactic Acid (PLA) is one of the most remarkable amphipathic polymers which make it one of the most suitable materials for polymeric micelles. Amphiphilic nanomaterial, such as Polyethylene Glycol (PEG), is one of the most promising carrier for tumor targeting. PLA-PEG as a copolymer has been generally utilized as drug delivery system for the various types of cancer. Chemotherapeutic drugs are stacked into PLA-PEG copolymer and as a result their duration time delays, hence medications arrive at specific tumor site.

Radiolabelling of nanomaterials for medical imaging and therapy

Nanomaterials offer unique physical, chemical and biological properties of interest for medical imaging and therapy. Over the last two decades, there has been an increasing effort to translate nanomaterial-based medicinal products (so-called nanomedicines) into clinical practice and, although multiple nanoparticle-based formulations are clinically available, there is still a disparity between the number of pre-clinical products and those that reach clinical approval. To facilitate the efficient clinical translation of nanomedicinal-drugs, it is important to study their whole-body biodistribution and pharmacokinetics from the early stages of their development. Integrating this knowledge with that of their therapeutic profile and/or toxicity should provide a powerful combination to efficiently inform nanomedicine trials and allow early selection of the most promising candidates. In this context, radiolabelling nanomaterials allows whole-body and non-invasive in vivo tracking by the sensitive clinical imaging techniques positron emission tomography (PET), and single photon emission computed tomography (SPECT). Furthermore, certain radionuclides with specific nuclear emissions can elicit therapeutic effects by themselves, leading to radionuclide-based therapy. To ensure robust information during the development of nanomaterials for PET/SPECT imaging and/or radionuclide therapy, selection of the most appropriate radiolabelling method and knowledge of its limitations are critical. Different radiolabelling strategies are available depending on the type of material, the radionuclide and/or the final application. In this review we describe the different radiolabelling strategies currently available, with a critical vision over their advantages and disadvantages. The final aim is to review the most relevant and up-to-date knowledge available in this field, and support the efficient clinical translation of future nanomedicinal products for in vivo imaging and/or therapy.

LHRH-conjugated, PEGylated, poly-lactide-co-glycolide nanocapsules for targeted delivery of combinational chemotherapeutic drugs Docetaxel and Quercetin for prostate cancer

One of the major challenges in effective cancer chemotherapy is the severe systemic cytotoxicities of anticancer drugs on healthy tissues. The present study reports chemically modified polymeric nanocapsules (NCs) encapsulating combination of chemotherapeutic drugs Docetaxel (DTX) and Quercetin (QU) for its active targeting to prostate cancer (PCa). The active targeting was achieved by conjugating Luteinizing-hormone-releasing hormone (LHRH) ligand to poly-lactide-co-glycolide (PLGA) using polyethylene glycol (PEG) as a spacer. The structure of the conjugates was characterized and confirmed using ¹H NMR and ATR-FTIR. The drug encapsulated NCs showed a homogenous size distribution with their size ranging between 120 and 150 nm, and exhibited a negative zeta potential in the range of -20 to -40 mV. The in vitro release studies highlighted the sustained drug release pattern from the respective NCs; while the PEG coating to polymeric NCs provided serum stability to the NCs. The in vitro biological evaluation of the NCs was conducted using PC-3 and LNCaP cell lines. The results of the cellular uptake studies showed a significantly higher untake of the LHRH targeted NCs, while the LHRH-targeted-PEGylated DTX: QU NCs exhibited higher caspase-3 activity. The cell viability assay results showed the enhanced cell inhibition activity of the combinatorial DTX: QU when compared to individual DTX. Further, higher cell cytotoxicity was achieved by LHRH-targeted DTX: QU NCs as compared to their free-form or non-targeted NCs. Finally, the results of in vivo tumor localization and in vivo antitumor activity studies complimented and upheld the in vitro results, demonstrating the beneficial role of PLGA-PEG-LHRH NCs encapsulating combination of DTX and QU in combating prostate cancer (PCa).

Cloxacillin benzathine-loaded polymeric nanocapsules: Physicochemical characterization, cell uptake, and intramammary antimicrobial effect

The present work shows the development and evaluation of the veterinary antibiotic cloxacillin benzathine (CLOXB) loaded into poly-ε-caprolactone (PCL) nanocapsules (NC), as a potential new treatment strategy to manage bovine intramammary infections, such as mastitis. Staphylococcus aureus-induced mastitis is often a recurrent disease due to the persistence of bacteria within infected cells. CLOXB-PCL NC were prepared by interfacial deposition of preformed biodegradable polymer followed by solvent displacement method. The mean diameter of NC varied from 241 to 428 nm and from 326 to 375 nm, when determined by dynamic light scattering and by atomic force microscopy, respectively. The zeta potential of NC was negative and varied from -28 to -51 mV. In vitro release studies from the NC were performed in two media under sink conditions: PBS with 1% polyethylene glycol or milk. A reversed-phase HPLC method was developed to determine the NC entrapment efficiency and kinetics of CLOXB release from the NC. Free CLOXB dissolution occurred very fast in both media, while drug release from the NC was slower and incomplete (below 50%) after 9 h. CLOXB release kinetics from polymeric NC was fitted with the Korsmeyer-Peppas model indicating that CLOXB release is governed by diffusion following Fick's law. The fluorescence confocal microscopy images of macrophage-like J774A.1 cells reveal NC uptake and internalization in vitro. In addition, antimicrobial effect of the intramammary administration of CLOXB-PCL NC in cows with mastitis resulted in no clinical signs of toxicity and allowed complete pathogen elimination after treatment. The in vivo results obtained in this work suggest that CLOXB-PCL NC could be a promising formulation for the treatment of intramammary infections in cattle, considering their physicochemical properties, release profiles and effects on bovine mastitis control.

Chloro-aluminium phthalocyanine loaded in ultradeformable liposomes for photobiology studies on human glioblastoma

Photodynamic therapy (PDT) has emerged as an alternative clinical protocol to treat brain tumors in early and advanced stages.

Metal complexes containing natural and and artificial radioactive elements and their applications

Recent advances (during the 2007–2014 period) in the coordination and organometallic chemistry of compounds containing natural and artificially prepared radionuclides (actinides and technetium), are reviewed. Radioactive isotopes of naturally stable elements are not included for discussion in this work. Actinide and technetium complexes with O-, N-, N,O, N,S-, P-containing ligands, as well π-organometallics are discussed from the view point of their synthesis, properties, and main applications. On the basis of their properties, several mono-, bi-, tri-, tetra- or polydentate ligands have been designed for specific recognition of some particular radionuclides, and can be used in the processes of nuclear waste remediation, i.e., recycling of nuclear fuel and the separation of actinides and fission products from waste solutions or for analytical determination of actinides in solutions; actinide metal complexes are also usefulas catalysts forcoupling gaseous carbon monoxide, as well as antimicrobial and anti-fungi agents due to their biological activity. Radioactive labeling based on the short-lived metastable nuclide technetium-99m (^99mTc) for biomedical use as heart, lung, kidney, bone, brain, liver or cancer imaging agents is also discussed. Finally, the promising applications of technetium labeling of nanomaterials, with potential applications as drug transport and delivery vehicles, radiotherapeutic agents or radiotracers for monitoring metabolic pathways, are also described.

Polyethylene glycol conjugated polymeric nanocapsules for targeted delivery of quercetin to folate-expressing cancer cells in vitro and in vivo

In this work we describe the formulation and characterization of chemically modified polymeric nanocapsules incorporating the anticancer drug, quercetin, for the passive and active targeting to tumors. Folic acid was conjugated to poly(lactide-co-glycolide) (PLGA) polymer to facilitate active targeting to cancer cells. Two different methods for the conjugation of PLGA to folic acid were employed utilizing polyethylene glycol (PEG) as a spacer. Characterization of the conjugates was performed using FTIR and (1)H NMR studies. The PEG and folic acid content was independent of the conjugation methodology employed. PEGylation has shown to reduce the size of the nanocapsule; moreover, zeta-potential was shown to be polymer-type dependent. Comparative studies on the cytotoxicity and cellular uptake of the different formulations by HeLa cells, in the presence and absence of excess folic acid, were carried out using MTT assay and Confocal Laser Scanning Microscopy, respectively. Both results confirmed the selective uptake and cytotoxicity of the folic acid targeted nanocapsules to the folate enriched cancer cells in a folate-dependent manner. Finally, the passive tumor accumulation and the active targeting of the nanocapsules to folate-expressing cells were confirmed upon intravenous administration in HeLa or IGROV-1 tumor-bearing mice. The developed nanocapsules provide a system for targeted delivery of a range of hydrophobic anticancer drugs in vivo.

Biodistribution and lymph node retention of polysaccharide-based immunostimulating nanocapsules

The adjuvant properties of polyglucosamine/squalene-based nanocapsules (PG-nanocapsules) associated with different subunit antigens has been previously reported. Thus, the aim of the present study was to monitor the biodistribution of PG-nanocapsules and their affinity for the draining lymph nodes after subcutaneous (s.c.) injection. The nanocapsules were efficiently radiolabeled with indium-111 ((111)In) (labeling efficiency of 98%). The diameter and zeta potential values of the unlabeled nanocapsules was preserved after the radiolabeling process and only 20% of the (111)In dissociated from the nanocapsules after 48h of incubation in serum. The radiolabeled nanocapsules and the control (111)InCl3 in saline solution (18.5MBq (500μCi) in 100μL) were injected s.c. in New Zealand White rabbits. The γ-scintigraphy imaging analysis revealed a slow clearance of the nanocapsules from the injection site and their progressive accumulation in the popliteal lymph node over time (3.8%±1.2 of the injected dose at 48h). Indeed, the clearance rate of the nanocapsules from the injection site was significantly slower than that of the control (free (111)InCl3), which rapidly drained into systemic circulation and accumulated mainly in excretion organs (i.e. kidneys and liver). In contrast, the biodistribution of nanocapsules was preferably limited to the lymphatic circulation. These results suggest that the immune potentiating effect previously observed for PG-nanocapsules is mainly due to the formation of a depot at the injection site, which was followed by a slow drainage into the lymphatic system and a prolonged retention in the lymph nodes.

Gemcitabine-loaded biocompatible nanocapsules for the effective treatment of human cancer

Aim: To encapsulate the nucleoside gemcitabine (GEM) in novel PEGylated polymeric nanocapsules (NanoGEM). Materials & methods: The biological activity of NanoGEM was tested both in vitro and in vivo in comparison with the free drug. The NanoGEM was made of polylactic acid and allowed the entrapment of a great amount of GEM. Results & discussion: The NanoGEM showed mean sizes of approximately 200 nm, a polydispersity index of approximately 0.1 and a ζ-potential of -30 mV. It exerted a stronger, quicker effect on the reduction of HEK293 cell growth in vitro in comparison with free GEM and had an in vivo antitumoral effect on the proliferation of xenograft tumors at a drug dosage tenfold less than its saline solution. The employment of nanocapsules increased the plasmatic half-life of the drug and allowed a great accumulation of GEM inside the tumors. Conclusion: NanoGEM represents a promising new tool for the treatment of cancer.

Original submitted 16 November 2011; Revised submitted 21 June 2012; Published online 24 October 2012

Emerging role of radiolabeled nanoparticles as an effective diagnostic technique

Nanomedicine is emerging as a promising approach for diagnostic applications. Nanoparticles are structures in the nanometer size range, which can present different shapes, compositions, charges, surface modifications, in vitro and in vivo stabilities, and in vivo performances. Nanoparticles can be made of materials of diverse chemical nature, the most common being metals, metal oxides, silicates, polymers, carbon, lipids, and biomolecules. Nanoparticles exist in various morphologies, such as spheres, cylinders, platelets, and tubes. Radiolabeled nanoparticles represent a new class of agent with great potential for clinical applications. This is partly due to their long blood circulation time and plasma stability. In addition, because of the high sensitivity of imaging with radiolabeled compounds, their use has promise of achieving accurate and early diagnosis. This review article focuses on the application of radiolabeled nanoparticles in detecting diseases such as cancer and cardiovascular diseases and also presents an overview about the formulation, stability, and biological properties of the nanoparticles used for diagnostic purposes.

Characterization of fluorescent poly(isobutylcyanoacrylate) nanoparticles obtained by copolymerization of a fluorescent probe during Redox Radical Emulsion Polymerization (RREP)

PURPOSE

The purpose of the work was to demonstrate that a polymerizable fluorescent labeled was incorporated in the core of chitosan/pluronic® F68-coated Poly(IsobutylCyanoAcrylate) (PIBCA) nanoparticles thanks to a covalent linkage. It was also aimed to show that the labeling did not modify the complement activation capacity of the nanoparticles which are designed as drug carriers for the in vivo delivery of siRNA.

METHOD

Fluorescent nanoparticles were prepared by adding a fluorescent monomer dye, methacryloxyethyl thiocarbamoyl rhodamine B during the preparation of nanoparticles by redox radical emulsion polymerization. The structure and composition of the fluorescent nanoparticles was investigated. The capacity of the fluorescent nanoparticles to activate the complement system was evaluated by 2D immunoelectrophoresis.

RESULTS

Results from the analysis of the composition and structure of polymers forming the nanoparticles showed that the fluorescent dye was incorporated in the core of the nanoparticles by formation of a stable covalent linkage with PIBCA. The labeled nanoparticles showed the same surface properties as the corresponding non-labeled nanoparticles based on analysis of the polymer structure, physicochemical properties and evaluation of their capacity to activate the complement system.

CONCLUSION

This work showed that the fluorescent PIBCA nanoparticles were labeled by incorporation of the fluorescent probe in the nanoparticle core and that the fluorescent probe did not modify the nanoparticle surface properties. These fluorescent nanoparticles can be proposed as relevant models to investigate how they deliver siRNA to their biological target in cell cultures and during in vivo experiments.

Formation of Pegylated polyurethane and Lysine-coated polyurea nanoparticles obtained from O/W nano-emulsions

The present work describes the formation of Pegylated polyurethane and Lysine-coated polyurea nanoparticles obtained from O/W nano-emulsions via an interfacial polycondensation process in the aqueous solution/polysorbate 80/diisocyanate/medium chain triglyceride systems. The initial nano-emulsions were prepared using the phase inversion composition (PIC) method. Dynamic light scattering studies revealed the changes in the particle size occurring during the process of nanoparticle formation. Well-defined polymeric nanoparticles with a small particle diameter (below 80 nm) and low polydispersity index were obtained using a highly hydrophilic component (polyethylene glycol or lysine) and an aliphatic diisocyante monomer. FT-IR and AFM studies showed that the polymeric matrix of nanoparticles was built by copolymers derived from reaction between the diisocyanate and the hydroxyl groups of both nonionic surfactant and the highly hydrophilic component. Pegylated-polyurethane and lysine-coated polyurea nanoparticles designed in this study are promising tools for future applications in biomedical sciences.

Recent advances in PEG-PLA block copolymer nanoparticles

Due to their small particle size and large and modifiable surface, nanoparticles have unique advantages compared with other drug carriers. As a research focus in recent years, polyethylene glycol-polylactic acid (PEG-PLA) block copolymer and its end-group derivative nanoparticles can enhance the drug loading of hydrophobic drugs, reduce the burst effect, avoid being engulfed by phagocytes, increase the circulation time of drugs in blood, and improve bioavailability. Additionally, due to their smaller particle size and modified surface, these nanoparticles can accumulate in inflammation or target locations to enhance drug efficacy and reduce toxicity. Recent advances in PEG-PLA block copolymer nanoparticles, including the synthesis of PEG-PLA and the preparation of PEG-PLA nanoparticles, were introduced in this study, in particular the drug release and modifiable characteristics of PEG-PLA nanoparticles and their application in pharmaceutical preparations.

Methods for the preparation and manufacture of polymeric nanoparticles

This review summarizes the different methods of preparation of polymer nanoparticles including nanospheres and nanocapsules. The first part summarizes the basic principle of each method of nanoparticle preparation. It presents the most recent innovations and progresses obtained over the last decade and which were not included in previous reviews on the subject. Strategies for the obtaining of nanoparticles with controlled in vivo fate are described in the second part of the review. A paragraph summarizing scaling up of nanoparticle production and presenting corresponding pilot set-up is considered in the third part of the review. Treatments of nanoparticles, applied after the synthesis, are described in the next part including purification, sterilization, lyophilization and concentration. Finally, methods to obtain labelled nanoparticles for in vitro and in vivo investigations are described in the last part of this review.