Preparation and characterization of polysaccharide-based nanoparticles with anticoagulant activity

Immune-stealth VP28-conjugated heparin nanoparticles for enhanced and reversible anticoagulation

Heparins are a family of sulfated linear negatively charged polysaccharides that have been widely used for their anticoagulant, antithrombotic, antitumor, anti-inflammatory, and antiviral properties. Additionally, it has been used for acute cerebral infarction relief as well as other pharmacological actions. However, heparin's self-aggregated macrocomplex may reduce blood circulation time and induce life-threatening thrombocytopenia (HIT) complicating the use of heparins. Nonetheless, the conjugation of heparin to immuno-stealth biomolecules may overcome these obstacles. An immunostealth recombinant viral capsid protein (VP28) was expressed and conjugated with heparin to form a novel nanoparticle (VP28-heparin). VP28-heparin was characterized and tested to determine its immunogenicity, anticoagulation properties, effects on total platelet count, and risk of inducing HIT in animal models. The synthesized VP28-heparin trimeric nanoparticle was non-immunogenic, possessed an average hydrodynamic size (8.81 ± 0.58 nm) optimal for the evasion renal filtration and reticuloendothelial system uptake (hence prolonging circulating half-life). Additionally, VP28-heparin did not induce mouse death or reduce blood platelet count when administered at a high dosein vivo(hence reducing HIT risks). The VP28-heparin nanoparticle also exhibited superior anticoagulation properties (2.2× higher prothrombin time) and comparable activated partial thromboplastin time, but longer anticoagulation period when compared to unfractionated heparin. The anticoagulative effects of the VP28-heparin can also be reversed using protamine sulfate. Thus, VP28-heparin may be an effective and safe heparin derivative for therapeutic use.

Quality-by-Design-Based Development of Rivaroxaban-Loaded Liquisolid Compact Tablets with Improved Biopharmaceutical Attributes

Rivaroxaban (RXN) finds use in the management of pulmonary embolism and deep vein thrombosis. Its poor solubility (5-7 µg/mL) and P-gp-mediated efflux from intestinal lining limits the oral application of RXN. This work assessed the impact of liquisolid compact technique in augmenting the solubility and bioavailability of RXN. PEG 400, Avicel PH 200, and Aerosil 200 were used as non-volatile liquid, carrier, and coating material, respectively, to formulate RXN liquid-solid compacts (RXN LSCs). A 32-factor factorial design was used in the optimisation to assess the impacts of factors (load factor and carrier:coating ratio) on the responses (angle of repose and Q30 min). Pre-compression parameters of RXN LSCs suggested adequate flow and compressibility. Optimisation data suggested significant influence of factors on both the responses. Optimised RXN LSC-based tablets showed a significantly higher in vitro dissolution rate than RXN API and Xarelto® tablets due to improved solubility, reduced crystallinity, greater surface area, and enhanced wetting of RXN particles. XRD, DSC, and SEM data supported RXN's amorphization. The cytotoxicity (MTT assay) and permeation studies indicated the nontoxicity of prepared RXN LSC tablets and the role of PEG 400 in inhibiting P-gp. Pharmacokinetic study of RXN LSC-based tablets in Albino Wistar rats exhibited 2.51- and 1.66-times higher AUC in comparison to RXN API and Xarelto® tablets respectively, demonstrating that developed formulation had a greater oral bioavailability. The RXN LSC tablets showed longer bleeding times and higher rates of platelet aggregation than RXN API. Thus, RXN LSC tablets can be considered a facile, scalable technology.

Amalgamation of solid dispersion and melt adsorption techniques for augmentation of oral bioavailability of novel anticoagulant rivaroxaban

The objective of the present study was to evaluate the potential of solid dispersion adsorbate (SDA) to improve the solubility and bioavailability of rivaroxaban (RXN). SDA of RXN was developed by fusion method using PEG 4000 as carrier and Neusilin as adsorbent. A 3² full factorial design was utilized to formulate various SDAs. The selected independent variables were the amount of carrier (X₁) and amount of adsorbent (X₂). The responses measured were the time required for 85% drug release (Y₁) and saturated solubility (Y₂). MTT assay was employed for cytotoxicity studies on Caco-2 cells. In vivo pharmacokinetics and pharmacodynamic evaluations were carried out to assess the prepared SDA. Pre-compression evaluation of SDA suggests the prepared batches (B1-B9) possess adequate flow properties and could be used for compression of tablets. Differential scanning calorimetry and X-ray diffraction data signified the conversion of the crystalline form of drug to amorphous form, a key parameter accountable for improvement in drug dissolution. Optimization data suggests that the amount of carrier and amount of adsorbent significantly (P < 0.05) influence both dependent variables. Post-compression data signifies that the compressibility behavior of prepared tablets was within the official standard limits. A significant increase (P < 0.0001) in the in vitro dissolution characteristics of RXN was noticed in optimized SDA (> 85% in 10 min) as compared to the pure drug, marketed product, and directly compressible tablet. Cytotoxicity studies confirmed the nontoxicity of prepared RXN SDA tablets. RXN SDA tablets exhibited 2.79- and 1.85-fold higher AUC in comparison to RXN suspension and Xarelto tablets respectively indicating improved oral bioavailability. Higher bleeding time and percentage of platelet aggregation noticed with RXN SDA tablets in comparison to RXN suspension further substantiate the efficacy of the prepared formulation. In summary, the results showed the potential of RXN SDA tablets to enhance the bioavailability of RXN and hence can be an alternate approach of solid dosage form for its development for commercial application.

Fucoidan-based nanoparticles: Preparations and applications

Nanoparticle-based therapy has gained much attention in the pharmaceutical industry. Fucoidan is a sulfated polysaccharide naturally derived from marine brown algae and is widely used for medical applications. We explore preparation of fucoidan-based nanoparticles and their biomedical applications in the current review. The fucoidan-based nanoparticles have been synthesized using microwave, emulsion, solvent evaporation, green synthesis, polyelectrolyte self-assembly, precipitation, and ultrasonication methods. The synthesized nanoparticles have particle sizes ranging from 100 to 400 nm. Therefore, fucoidan-based nanoparticles have a variety of potential therapeutic applications, including drug delivery, cancer therapies, tissue engineering, antimicrobial applications, magnetic resonance imaging contrast, and atherothrombosis imaging. For example, fucoidan nanoparticles have been used to deliver curcumin, dextran, gentamicin, epigallocatechin gallate, and cisplatin for cancer therapies. Furthermore, fucoidan nanoparticles coupled with metal nanoparticles have been used to target and recognize clinical conditions for diagnostic purposes. Hence, fucoidan-based nanoparticles have been helpful for biomedical applications.

Repurposing of Marine Raw Materials in the Formulation of Innovative Plant Protection Products

Over the years, the growth of the world population has caused a huge agricultural production to support the population's needs. Since plant protection products are essential to preserve agricultural crops and to optimize vital plant processes, it is crucial to use more sustainable, biodegradable, and biocompatible raw materials, without harming the environment and human health. Although the development of new plant protection products is a costly process, the environmental benefits should be considered. In this context, marine raw materials obtained as byproducts of fishing industries, possessing a wide variety of physicochemical and biological properties, can serve as a promising source of such materials. They have a high potential for developing alternative and safe formulations for agricultural applications, not only as biocompatible excipients but also as effective and selective, or even both. It is also possible to promote a synergistic effect between an active substance and the biological activity of the marine polymer used in the formulation, enabling plant protection products with lower concentrations of the active substances. Thus, this review addresses the repurposing of marine raw materials for the development of innovative plant protection products, focusing on micro- and nanoparticulate formulations, to protect the environment through more ecological and sustainable strategies.

Immunomodulatory effects of polysaccharides from marine algae for treating cancer, infectious disease, and inflammation

A significant rise in the occurrence and severity of adverse reactions to several synthetic drugs has fueled considerable interest in natural product-based therapeutics. In humans and animals, polysaccharides from marine microalgae and seaweeds have immunomodulatory effects. In addition, these polysaccharides may possess antiviral, anticancer, hypoglycemic, anticoagulant, and antioxidant properties. During inflammatory diseases, such as autoimmune diseases and sepsis, immunosuppressive molecules can serve as therapeutic agents. Similarly, molecules that participate in immune activation can induce immune responses against cancer and infectious diseases. We aim to discuss the chemical composition of the algal polysaccharides, namely alginate, fucoidan, ascophyllan, and porphyran. We also summarize their applications in the treatment of cancer, infectious disease, and inflammation. Recent applications of nanoparticles that are based on algal polysaccharides for the treatment of cancer and inflammatory diseases have also been addressed. In conclusion, these applications of marine algal polysaccharides could provide novel therapeutic alternatives for several diseases.

Influence of nanoparticles on the haemostatic balance: between thrombosis and haemorrhage

Maintenance of a delicate haemostatic balance or a balance between clotting and bleeding is critical to human health. Irrespective of administration route, nanoparticles can reach the bloodstream and might interrupt the haemostatic balance by interfering with one or more components of the coagulation, anticoagulation, and fibrinolytic systems, which potentially lead to thrombosis or haemorrhage. However, inadequate understanding of their effects on the haemostatic balance, along with the fact that most studies mainly focus on the functionality of nanoparticles while forgetting or leaving behind their risk to the body's haemostatic balance, is a major concern. Hence, our review aims to provide a comprehensive depiction of nanoparticle-haemostatic balance interactions, which has not yet been covered. The synergistic roles of cells and plasma factors participating in haemostatic balance are presented. Possible interactions and interference of each type of nanoparticle with the haemostatic balance are comprehensively discussed, particularly focusing on the underlying mechanisms. Interactions of nanoparticles with innate immunity potentially linked to haemostasis are mentioned. Various physicochemical characteristics that influence the nanoparticle-haemostatic balance are detailed. Challenges and future directions are also proposed. This insight would be valuable for the establishment of nanoparticles that can either avoid unintended interference with the haemostatic balance or purposely downregulate/upregulate its key components in a controlled manner.

Thrombus-specific theranostic nanocomposite for codelivery of thrombolytic drug, algae-derived anticoagulant and NIR fluorescent contrast agent

Thrombolysis is a standard treatment for rapidly restoring blood flow. However, the application of urokinase-type plasminogen activator (Uk) in clinical therapy is limited due to its nonspecific distribution and inadequate therapeutic accumulation. Precise thrombus imaging and site-specific drug delivery can enhance the diagnostic and therapeutic efficacy for thrombosis. Accordingly, we developed a P-selectin-specific, photothermal theranostic nanocomposite for thrombus-targeted codelivery of Uk and indocyanine green (ICG, a contrast agent for near-infrared (NIR) fluorescence imaging). We evaluated its capabilities for thrombus imaging and enzyme/hyperthermia combined thrombolytic therapy. Mesoporous silica-coated gold nanorods (Si-AuNRs) were functionalized with an arginine-rich peptide to create an organic template for the adsorption of ICG and fucoidan (Fu), an algae-derived anticoagulant. Uk was loaded into the SiO₂ pores of the Si-AuNRs through the formation of a Fu-Uk-ICG complex on the peptide-functionalized template. The Fu-Uk/ICG@SiAu NRs nanocomposite increased the photostability of ICG and improved its targeting/accumulation at blood clot sites with a strong NIR fluorescence intensity for precise thrombus imaging. Furthermore, ICG incorporated into the nanocomposite enhanced the photothermal effect of Si-AuNRs. Fu, as a P-selectin-targeting ligand, enabled the nanocomposite to target a thrombus site where platelets were activated. The nanocomposite enabled a faster release of Uk for rapid clearing of blood clots and a slower release of Fu for longer lasting prevention of thrombosis regeneration. The nanocomposite with multiple functions, including thrombus-targeting drug delivery, photothermal thrombolysis, and NIR fluorescence imaging, is thus an advanced theranostic platform for thrombolytic therapy with reduced hemorrhaging risk and enhanced imaging/thrombolysis efficiency. STATEMENT OF SIGNIFICANCE: Herein, for the first time, a P-selectin specific, photothermal theranostic nanocomposite for thrombus-targeted co-delivery of urokinase and NIR fluorescence contrast agent indocyanine green (ICG) was developed. We evaluated the potential of this theranostic nanocomposite for thrombus imaging and enzyme/hyperthermia combined thrombolytic therapy. The nanocomposite showed multiple functions including thrombus targeting and imaging, and photothermal thrombolysis. Besides, it allowed faster release of the thrombolytic urokinase for rapidly clearing blood clots and slower release of a brown algae-derived anticoagulant fucoidan (also acting as a P-selectin ligand) for prevention of thrombosis regeneration. The nanocomposite is thus a new and advanced theranostic platform for targeted thrombolytic therapy.

Nanocarriers in the Delivery of Hydroxychloroquine to the Respiratory System: An Alternative to COVID-19

In response to the global outbreak caused by SARS-CoV-2, this article aims to propose the development of nanosystems for the delivery of hydroxychloroquine in the respiratory system to the treatment of COVID-19. A descriptive literature review was conducted, using the descriptors "COVID-19", "Nanotechnology", "Respiratory Syndrome" and "Hydroxychloroquine", in the PubMed, ScienceDirect and SciElo databases. After analyzing the articles according to the inclusion and exclusion criteria, they were divided into 3 sessions: Coronavirus: definitions, classifications and epidemiology, pharmacological aspects of hydroxychloroquine and pharmaceutical nanotechnology in targeting of drugs. We used 131 articles published until July 18, 2020. Hydroxychloroquine seems to promote a reduction in viral load, in vivo studies, preventing the entry of SARS-CoV-2 into lung cells, and the safety of its administration is questioned due to the toxic effects that it can develop, such as retinopathy, hypoglycemia and even cardiotoxicity. Nanosystems for the delivery of drugs in the respiratory system may be a viable alternative for the administration of hydroxychloroquine, which may enhance the therapeutic effect of the drug with a consequent decrease in its toxicity, providing greater safety for implementation in the clinic in the treatment of COVID-19.

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.

Possibilities of Fucoidan Utilization in the Development of Pharmaceutical Dosage Forms

Fucoidan is a polysaccharide built from L-fucose molecules. The main source of this polysaccharide is the extracellular matrix of brown seaweed (Phaeophyta), but it can be also isolated from invertebrates such as sea urchins (Echinoidea) and sea cucumbers (Holothuroidea). Interest in fucoidan is related to its broad biological activity, including possible antioxidant, anti-inflammatory, antifungal, antiviral or antithrombotic effects. The potential application of fucoidan in the pharmaceutical technology is also due to its ionic nature. The negative charge of the molecule results from the presence of sulfate residues in the C-2 and C-4 positions, occasionally in C-3, allowing the formation of complexes with other oppositely charged molecules. Fucoidan is non-toxic, biodegradable and biocompatible compound approved by Food and Drug Administration (FDA) as Generally Recognized As Safe (GRAS) category as food ingredient. Fucoidan plays an important role in the pharmaceutical technology, so in this work aspects concerning its pharmaceutical characteristics and designing of various dosage forms (nanoparticles, liposomes, microparticles, and semisolid formulations) with fucoidan itself and with its combinations with other polymers or components that give a positive charge were reviewed. Advantages and limitations of fucoidan utilization in the pharmaceutical technology were also discussed.

Nanoparticles for hematologic diseases detection and treatment

Nanotechnology, as an interdisciplinary science, combines engineering, physics, material sciences, and chemistry with the biomedicine knowhow, trying the management of a wide range of diseases. Nanoparticle-based devices holding tumor imaging, targeting and therapy capabilities are formerly under study. Since conventional hematological therapies are sometimes defined by reduced selectivity, low therapeutic efficacy and many side effects, in this review we discuss the potential advantages of the NPs' use in alternative/combined strategies. In the introduction the basic notion of nanomedicine and nanoparticles' classification are described, while in the main text nanodiagnostics, nanotherapeutics and theranostics solutions coming out from the use of a wide-ranging NPs availability are listed and discussed.

Application of pH-Responsive Fucoidan/Chitosan Nanoparticles to Improve Oral Quercetin Delivery

Polymeric nanoparticles based on fucoidan and chitosan were developed to deliver quercetin as a novel functional food. Through the polyelectrolyte self-assembly method, fucoidan/chitosan (F/C) nanoparticles were obtained with three different weight ratios (1/1, 3/1, and 5/1). The content of quercetin in the fucoidan/chitosan nanoparticles was in the range 110 ± 3 to 335 ± 4 mg·mL^-1, with the increase of weight ratio of fucoidan to chitosan in the nanoparticle. Physicochemically stable nanoparticles were obtained with a particle size within the 300⁻400 nm range and surface potential higher than +30 mV for the 1F/1C ratio nanoparticle and around -30 mV for the 3F/1C and 5F/1C ratios nanoparticles. The 1F/1C ratio nanoparticle became larger and more unstable as the pH increased from 2.5 to 7.4, while the 3F/1C and 5F/1C nanoparticles retained their initial characteristics. This result indicates that the latter nanoparticles were stable along the gastrointestinal tract. The quercetin-loaded fucoidan/chitosan nanoparticles showed strong antioxidant activity and controlled release under simulated gastrointestinal environments (in particular for the 3F/1C and 5F/1C ratios), preventing quercetin degradation and increasing its oral bioavailability.

Synthesis and antitumor evaluation of hybrids of 5,8-dioxo-5,8-dihydroisoquinoline-4-carboxylates and carbohydrates

Aim: Cancer has emerged as a growing public health problem in many parts of the world. Methodology: We describe the synthesis of a series of carbohydrate-based isoquinoline-5,8-diones through the 1,4-addition reaction between 5,8-dioxo-5,8-dihydroisoquinoline and aminocarbohydrates. Halogenated quinones were also synthesized. Their inhibitory effects on the proliferation of human cancer cell lines were studied. Results & conclusion: The most promising compound, derived from isoquinoline-5,8-dione, containing ribofuranosidyl ring, was selectively active in vitro against H1299 cancer cells, with 1.7-fold higher activity than that of vinorelbine tartrate. This result suggests that the glycoconjugate in question may constitute a valuable lead compound to design and synthesize a more active and less toxic derivative with respect to the development of a new antitumor substance.

A promising oral fucoidan-based antithrombotic nanosystem: Development, activity and safety

Fucoidan-loaded nanoparticles emerge as great candidates to oral anticoagulant therapy, due to increasing of bioavailability and circulation time of this natural anticoagulant. Crosslink between chitosan chains are performed using glutaraldehyde to confer higher gastric pH resistance to nanoparticle matrices. In this work, chitosan-fucoidan nanoparticles, without (NpCF) and with glutaraldehyde crosslink (NpCF 1% and NpCF 2%), were prepared to evaluate their anticoagulant, antithrombotic and hemorrhagic profile. Nanoparticles were characterized by average diameter, polydispersity index, zeta potential, Fourier transform infrared spectroscopy and fucoidan in vitro release. Anticoagulant and antithrombotic activities were determined by in vitro and in vivo models, respectively. Hemorrhagic profile was in vivo evaluated by tail bleeding assay. Preparations showed nanometric and homogeneous average diameters. Zeta potentials of NpCF and NpCF 1% were stable over gastrointestinal pH range, which was confirmed by low fucoidan release in gastric and enteric media. In pH 7.4, NpCF and NpCF 1% demonstrated fucoidan release of 65.5% and 60.6%, respectively, within the first 24 hours. In comparison to fucoidan, NpCF and NpCF 1% showed increased in vitro anticoagulant activity. A significant difference on oral antithrombotic profile of NpCF 1% was found in comparison to fucoidan. Bleeding profile of NpCF and NpCF 1% showed no differences to control group, indicating the safety of these systems. Surprisingly, oral antithrombotic profile of commercially available fucoidan, from Fucus vesiculosus, has not been previously determined, which reveals new possibilities. In this work, significant advances were observed in anticoagulant and antithrombotic profiles of fucoidan through the preparation of NpCF 1%.

Chitosan/sulfated locust bean gum nanoparticles: In vitro and in vivo evaluation towards an application in oral immunization

This work proposes the design of nanoparticles based on locus bean gum (LBG) and chitosan to be used as oral immunoadjuvant for vaccination purposes. LBG-based nanoparticles were prepared by mild polyelectrolyte complexation between chitosan (CS) and a synthesized LBG sulfate derivative (LBGS). Morphological characterization suggested that nanoparticles present a solid and compact structure with spherical-like shape. Sizes around 180-200nm and a positive surface charge between +9mV and +14mV were obtained. CS/LBGS nanoparticles did not affect cell viability of Caco-2 cells after 3h and 24h of exposure when tested at concentrations up to 1.0mg/mL. Two model antigens (a particulate acellular extract HE of Salmonella enterica serovar Enteritidis, and ovalbumin as soluble antigen) were associated to CS/LBGS nanoparticles with efficiencies around 26% for ovalbumin and 32% for HE, which resulted in loading capacities up to 12%. The process did not affect the antigenicity of the associated antigens. BALB/c mice were orally immunized with ovalbumin-loaded nanoparticles (100μg), and results indicate an adjuvant effect of the CS/LBGS nanoparticles, eliciting a balanced Th1/Th2 immune response. Thus, CS/LBGS nanoparticles are promising as antigen mucosal delivery strategy, with particular interest for oral administration.

Fucoidans in Nanomedicine

Fucoidans are widespread cost-effective sulfated marine polysaccharides which have raised interest in the scientific community over last decades for their wide spectrum of bioactivities. Unsurprisingly, nanomedicine has grasped these compounds to develop innovative therapeutic and diagnostic nanosystems. The applications of fucoidans in nanomedicine as imaging agents, drug carriers or for their intrinsic properties are reviewed here after a short presentation of the main structural data and biological properties of fucoidans. The origin and the physicochemical specifications of fucoidans are summarized in order to discuss the strategy of fucoidan-containing nanosystems in Human health. Currently, there is a need for reproducible, well characterized fucoidan fractions to ensure significant progress.

Platelet lysate and chondroitin sulfate loaded contact lenses to heal corneal lesions

Hemoderivative tear substitutes contain various ephiteliotrophic factors, such as growth factors (GF), involved in ocular surface homeostasis without immunogenic properties. The aim of the present work was the loading of platelet lysate into contact lenses to improve the precorneal permanence of platelet lysate growth factors on the ocular surface to enhance the treatment of corneal lesions. To this purpose, chondroitin sulfate, a sulfated glycosaminoglycan, which is normally present in the extracellular matrix, was associated with platelet lysate. In fact, chondroitin sulfate is capable of electrostatic interaction with positively charged growth factors, in particular, with bFGF, IGF, VEGF, PDGF and TGF-β, resulting in their stabilization and reduced degradation in solution. In the present work, various types of commercially available contact lenses have been loaded with chondroitin sulfate or chondroitin sulfate in association with platelet lysate to achieve a release of growth factors directly onto the corneal surface lesions. One type of contact lenses (PureVision(®)) showed in vitro good proliferation properties towards corneal cells and were able to enhance cut closure in cornea constructs.

Sulfated Seaweed Polysaccharides as Multifunctional Materials in Drug Delivery Applications

In the last decades, the discovery of metabolites from marine resources showing biological activity has increased significantly. Among marine resources, seaweed is a valuable source of structurally diverse bioactive compounds. The cell walls of marine algae are rich in sulfated polysaccharides, including carrageenan in red algae, ulvan in green algae and fucoidan in brown algae. Sulfated polysaccharides have been increasingly studied over the years in the pharmaceutical field, given their potential usefulness in applications such as the design of drug delivery systems. The purpose of this review is to discuss potential applications of these polymers in drug delivery systems, with a focus on carrageenan, ulvan and fucoidan. General information regarding structure, extraction process and physicochemical properties is presented, along with a brief reference to reported biological activities. For each material, specific applications under the scope of drug delivery are described, addressing in privileged manner particulate carriers, as well as hydrogels and beads. A final section approaches the application of sulfated polysaccharides in targeted drug delivery, focusing with particular interest the capacity for macrophage targeting.

Seaweed Polysaccharide-Based Nanoparticles: Preparation and Applications for Drug Delivery

In recent years, there have been major advances and increasing amounts of research on the utilization of natural polymeric materials as drug delivery vehicles due to their biocompatibility and biodegradability. Seaweed polysaccharides are abundant resources and have been extensively studied for several biological, biomedical, and functional food applications. The exploration of seaweed polysaccharides for drug delivery applications is still in its infancy. Alginate, carrageenan, fucoidan, ulvan, and laminarin are polysaccharides commonly isolated from seaweed. These natural polymers can be converted into nanoparticles (NPs) by different types of methods, such as ionic gelation, emulsion, and polyelectrolyte complexing. Ionic gelation and polyelectrolyte complexing are commonly employed by adding cationic molecules to these anionic polymers to produce NPs of a desired shape, size, and charge. In the present review, we have discussed the preparation of seaweed polysaccharide-based NPs using different types of methods as well as their usage as carriers for the delivery of various therapeutic molecules (e.g., proteins, peptides, anti-cancer drugs, and antibiotics). Seaweed polysaccharide-based NPs exhibit suitable particle size, high drug encapsulation, and sustained drug release with high biocompatibility, thereby demonstrating their high potential for safe and efficient drug delivery.

Biocompatibility and Stability of Polysaccharide Polyelectrolyte Complexes Aimed at Respiratory Delivery

Chitosan (CS) and chondroitin sulfate (CHS) are natural polymers with demonstrated applicability in drug delivery, while nanoparticles are one of the most explored carriers for transmucosal delivery of biopharmaceuticals. In this work we have prepared CS/CHS nanoparticles and associated for the first time the therapeutic protein insulin. Fluorescein isothiocyanate bovine serum albumin (FITC-BSA) was also used to enable comparison of behaviors regarding differences in molecular weight (5.7 kDa versus 67 kDa). Nanoparticles of approximately 200 nm and positive zeta potential around +20 mV were obtained. These parameters remained stable for up to 1 month at 4 °C. Proteins were associated with efficiencies of more than 50%. The release of FITC-BSA in PBS pH 7.4 was more sustained (50% in 24 h) than that of insulin (85% in 24 h). The biocompatibility of nanoparticles was tested in Calu-3 and A549 cells by means of three different assays. The metabolic assay MTT, the determination of lactate dehydrogenase release, and the quantification of the inflammatory response generated by cell exposure to nanoparticles have indicated an absence of overt toxicity. Overall, the results suggest good indications on the application of CS/CHS nanoparticles in respiratory transmucosal protein delivery, but the set of assays should be widened to clarify obtained results.

Effect of the silicon carbide nanoparticles introduction on biological properties of porous polymer coatings

The multilayer polyelectrolyte films (PEMs) seem to be a promising material to reconstruct the structure and behavior of the extracellular matrix.

Delivery of berberine using chitosan/fucoidan-taurine conjugate nanoparticles for treatment of defective intestinal epithelial tight junction barrier

Bacterial-derived lipopolysaccharides (LPS) can cause defective intestinal barrier function and play an important role in the development of inflammatory bowel disease. In this study, a nanocarrier based on chitosan and fucoidan was developed for oral delivery of berberine (Ber). A sulfonated fucoidan, fucoidan-taurine (FD-Tau) conjugate, was synthesized and characterized by Fourier transform infrared (FTIR) spectroscopy. The FD-Tau conjugate was self-assembled with berberine and chitosan (CS) to form Ber-loaded CS/FD-Tau complex nanoparticles with high drug loading efficiency. Berberine release from the nanoparticles had fast release in simulated intestinal fluid (SIF, pH 7.4), while the release was slow in simulated gastric fluid (SGF, pH 2.0). The effect of the berberine-loaded nanoparticles in protecting intestinal tight-junction barrier function against nitric oxide and inflammatory cytokines released from LPS-stimulated macrophage was evaluated by determining the transepithelial electrical resistance (TEER) and paracellular permeability of a model macromolecule fluorescein isothiocyanate-dextran (FITC-dextran) in a Caco-2 cells/RAW264.7 cells co-culture system. Inhibition of redistribution of tight junction ZO-1 protein by the nanoparticles was visualized using confocal laser scanning microscopy (CLSM). The results suggest that the nanoparticles may be useful for local delivery of berberine to ameliorate LPS-induced intestinal epithelia tight junction disruption, and that the released berberine can restore barrier function in inflammatory and injured intestinal epithelial.

Significance of algal polymer in designing amphotericin B nanoparticles

Development of oral amphotericin B (AmB) loaded nanoparticles (NPs) demands a novel technique which reduces its toxicity and other associated problems. Packing of AmB in between two oppositely charged ions by polyelectrolyte complexation technique proved to be a successful strategy. We have developed a novel carrier system in form of polyelectrolyte complex of AmB by using chitosan (CS) and porphyran (POR) as two oppositely charged polymers with TPP as a crosslinking agent. Initially POR was isolated from Porphyra vietnamensis followed by the fact that its alkali induced safe reduction in molecular weight was achieved. Formulation was optimized using three-factor three-level (3³) central composite design. High concentration of POR in NPs was confirmed by sulfated polysaccharide (SP) assay. Degradation and dissolution studies suggested the stability of NPs over wide pH range. Hemolytic toxicity data suggested the safety of prepared formulation. In vivo and in vitro antifungal activity demonstrated the high antifungal potential of optimized formulation when compared with standard drug and marketed formulations. Throughout the study TPP addition did not cause any significant changes. Therefore, these experimental oral NPs may represent an interesting carrier system for the delivery of AmB.

Critical evaluation of biodegradable polymers used in nanodrugs

Use of biodegradable polymers for biomedical applications has increased in recent decades due to their biocompatibility, biodegradability, flexibility, and minimal side effects. Applications of these materials include creation of skin, blood vessels, cartilage scaffolds, and nanosystems for drug delivery. These biodegradable polymeric nanoparticles enhance properties such as bioavailability and stability, and provide controlled release of bioactive compounds. This review evaluates the classification, synthesis, degradation mechanisms, and biological applications of the biodegradable polymers currently being studied as drug delivery carriers. In addition, the use of nanosystems to solve current drug delivery problems are reviewed.

Poly ɛ-caprolactone nanoparticles loaded with Uncaria tomentosa extract: preparation, characterization, and optimization using the Box-Behnken design

PURPOSE

The aim of this research was to develop and optimize a process for obtaining poly ɛ-caprolactone (PCL) nanoparticles loaded with Uncaria tomentosa (UT) extract.

METHODS

Nanoparticles were produced by the oil-in-water emulsion solvent evaporation method. Preliminary experiments determined the initial conditions of the organic phase (OP) and of the aqueous phase (AP) that would be utilized for this study. Ultimately, a three-factor three-level Box-Behnken design (BBD) was employed during the optimization process. PCL and polyvinyl alcohol (PVA) concentrations (X(1) and X(2), respectively) and the AP/OP volume ratio (X(3)) were the independent variables studied, while entrapment efficiency (Y(1)), particle mean diameter (Y(2)), polydispersity (Y(3)), and zeta potential (Y(4)) served as the evaluated responses.

RESULTS

PRELIMINARY EXPERIMENTS REVEALED THAT THE OPTIMAL INITIAL CONDITIONS FOR THE PREPARATION OF NANOPARTICLES WERE AS FOLLOWS: OP composed of 5 mL ethyl acetate/acetone (3/2) mixture containing UT extract and PCL, and an AP of buffered PVA (pH 7.5) solution. Statistical analysis of the BBD results indicated that all of the studied factors had significant effects on the responses Y(1), Y(2), and Y(4,) and these effects are closely described or fitted by regression equations. Based on the obtained models and the selected desirability function, the nanoparticles were optimized to maximize Y(1) and minimize Y(2). These optimal conditions were achieved using 3% (w/v) PCL, 1% (w/v) PVA, and an AP/OP ratio of 1.7, with predicted values of 89.1% for Y(1) and 280 nm for Y(2). Another batch was produced under the same optimal conditions. The entrapment efficiency of this new batch was measured at 81.6% (Y(1)) and the particles had a mean size of 247 nm (Y(2)) and a polydispersity index of 0.062 (Y(3)).

CONCLUSION

This investigation obtained UT-loaded nanoparticle formulations with desired characteristics. The BBD approach was a useful tool for nanoparticle development and optimization, and thus should be useful especially in the realm of phytotherapeutics, in which varied compositions may be assessed in quantitative and qualitative terms.