Polyionic complexes of chitosan-N-arginine with alginate as pH responsive and mucoadhesive particles for oral drug delivery applications

Supramolecular oral delivery technologies for polypeptide-based drugs

Oral supramolecular drug delivery systems (SDDSs) have shown promising potential, along with a rapid increase in the development of polypeptide-based drugs. Biofriendly, biocompatible, and multistimulation-responsive SDDSs achieve their unique deliverability via noncovalent bonds, which can encapsulate drugs and release them at the target site along the oral tract. In this review, we analyze the oral tract from an anatomical perspective and explain the potential physical, microenvironmental, and systematic barriers, as well as the properties of drug delivery. After understanding the specific environment at different oral sites, the application of SDDSs to the mouth, stomach, small intestine, and cell targeting is summarized. Finally, this review summarizes the application of SDDSs for the successful delivery of drugs and describes how to overcome the barriers of SDDSs in drug delivery using a more biofriendly approach.

Hybrid crystalline bioparticles with nanochannels encapsulating acemannan from Aloe vera: Structure and interaction with lipid membranes

Smart nanocarrier-based bioactive delivery systems are a current focus in nanomedicine for allowing and boosting diverse disease treatments. In this context, the design of hybrid lipid-polymer particles can provide structure-sensitive features for tailored, triggered, and stimuli-responsive devices. In this work, we introduce hybrid cubosomes that have been surface-modified with a complex of chitosan-N-arginine and alginate, making them pH-responsive. We achieved high-efficiency encapsulation of acemannan, a bioactive polysaccharide from Aloe vera, within the nanochannels of the bioparticle crystalline structure and demonstrated its controlled release under pH conditions mimicking the gastric and intestinal environments. Furthermore, an acemannan-induced phase transition from Im3m cubic symmetry to inverse hexagonal HII phase enhances the bioactive delivery by compressing the lattice spacing of the cubosome water nanochannels, facilitating the expulsion of the encapsulated solution. We also explored the bioparticle interaction with membranes of varying curvatures, revealing thermodynamically driven affinity towards high-curvature lipid membranes and inducing morphological transformations in giant unilamellar vesicles. These findings underscore the potential of these structure-responsive, membrane-active smart bioparticles for applications such as pH-triggered drug delivery platforms for the gastrointestinal tract, and as modulators and promoters of cellular internalization.

Design of an antioxidant powder additive based on carvacrol encapsulated into a multilayer chitosan-alginate-maltodextrin emulsion

Carvacrol has demonstrated antioxidant activity; however, its high volatility and low water solubility limit its direct application in food matrices. Then, an effective encapsulation system is required to protect it. This study aimed to design and characterize a carvacrol-based additive encapsulated in a spray-dried multilayer emulsion based on chitosan/sodium alginate/maltodextrin. Spray-drying temperature of 120 °C and 3 %(w/w) maltodextrin content maximized both encapsulation efficiency (~97 %) and loading capacity (~53 %). The powder's antioxidant properties were evaluated in two food simulant media: water (SiW) and water-ethanol (SiD). The highest antioxidant activity was observed in SiW for both ABTS•+ (8.2 ± 0.3mgEAG/g) and FRAP (4.1 ± 0.2mgEAG/g) methods because of the reduced release of carvacrol in SiD vs. SiW, as supported by micro- and macrostructural observations by SAXS and microscopy, respectively. An increase from 143 to 157 °C attributable to carvacrol protection and Tg = 44.4 °C (> ambient) were obtained by TGA and DSC, respectively. FT-IR confirmed intermolecular interactions (e.g. -COO- and -NH3+) as well as H-bonding formation. High water solubility (81 ± 3 %), low hygroscopicity (8.8 ± 0.2 %(w/w), poor flowability (CI:45 ± 4), and high cohesiveness (HR:1.8 ± 0.1) between particles were achieved, leading to a powdered antioxidant additive with high potential for applications which required avoiding/reducing oxidation on hydrophilic and hydrophobic food products.

New approaches for modulation of alginate-chitosan delivery properties

Alginate is a biopolymer widely used on delivery systems when bioactive protection at acidic pH is required, while chitosan can enhance mucoadhesion and controlled release at alkaline pHs. In this work, alginate ionotropic gelation and electrostatic complexation to chitosan were evaluated concomitantly or in a two-step approach to improve the delivery properties of systems in different pHs. The effect of pH on alginate gelation and chitosan interactions were also evaluated. Alginate microspheres were prepared by ionotropic gelation in CaCl2 at different pH values (2.5 and 6.0) by extrusion. Complexation with chitosan was carried out during alginate ionotropic gelation (one-step approach) or after alginate gel formation (two-step approach). Alginate microparticles without chitosan showed larger pores and lower mechanical strength. Extruded microspheres at pH 6.0 were more stable to pH and showed smaller pores than the formed at pH 2.5. One-step production retained a large amount of bioactive at pH 7.0 and resulted in lower release at the pH of intestinal digestion. The two-step approach retained less amount of bioactive but confer more protection to the pH of the stomach phase and higher release in pH of the intestinal phase than one-step samples. These results indicate that the formation of alginate gels by ionotropic gelation followed by the complexation with chitosan (in two-step) is promising for the transport and delivery of bioactives into intestinal conditions, whereas the ionotropic gelation concomitantly to electrostatic complexation (one-step approach) is indicated to the delivery of bioactives into lower pH environments.

Antibacterial polypeptide-bioparticle for oral administration: Powder formulation, palatability and in vivo toxicity approach

The upsurge of bacterial resistance to conventional antibiotics turned a well-recognized public health threat. The need of developing new biomaterials of effective practical use in order to tackle bacterial resistance became urgent. In this study, a submicrometric bioparticle of known antibacterial activity was produced in powder form with suitable texture and appealing characteristics for effective oral administration. Through complex coacervating a natural-source antimicrobial polypeptide with chitosan-N-arginine and alginate, the bioactive polypeptide was physically incorporated to the bioparticle whose structure positively responds to the pH variations found in gastrointestinal tract. The powder formulation presented high palatability that was evaluated using fish as in vivo animal model. A thorough survey of the fish intestinal tissues, following a systematic oral administration, revealed high penetration potential of the biomaterial through epithelial cells and deeper intestine layers. Despite, no cytotoxic effect was observed in analyzing the tissues through different histology methods. The absence of intestinal damage was corroborated by immune histochemistry, being the integrity of epithelial motor myosin Vb and related traffic proteins preserved. Hematology further endorsed absence of toxicity in blood cells whose morphology was evaluated in detail. The study evidenced the applicability potential of a new biomaterial of appealing and safe oral administration of antibacterial polypeptide.

Recent developments in natural biopolymer based drug delivery systems

Targeted delivery of drug molecules to diseased sites is a great challenge in pharmaceutical and biomedical sciences. Fabrication of drug delivery systems (DDS) to target and/or diagnose sick cells is an effective means to achieve good therapeutic results along with a minimal toxicological impact on healthy cells. Biopolymers are becoming an important class of materials owing to their biodegradability, good compatibility, non-toxicity, non-immunogenicity, and long blood circulation time and high drug loading ratio for both macros as well as micro-sized drug molecules. This review summarizes the recent trends in biopolymer-based DDS, forecasting their broad future clinical applications. Cellulose chitosan, starch, silk fibroins, collagen, albumin, gelatin, alginate, agar, proteins and peptides have shown potential applications in DDS. A range of synthetic techniques have been reported to design the DDS and are discussed in the current study which is being successfully employed in ocular, dental, transdermal and intranasal delivery systems. Different formulations of DDS are also overviewed in this review article along with synthesis techniques employed for designing the DDS. The possibility of these biopolymer applications points to a new route for creating unique DDS with enhanced therapeutic qualities for scaling up creative formulations up to the clinical level.

Chitosan: A Potential Biopolymer in Drug Delivery and Biomedical Applications

Chitosan, a biocompatible and biodegradable polysaccharide derived from chitin, has surfaced as a material of promise for drug delivery and biomedical applications. Different chitin and chitosan extraction techniques can produce materials with unique properties, which can be further modified to enhance their bioactivities. Chitosan-based drug delivery systems have been developed for various routes of administration, including oral, ophthalmic, transdermal, nasal, and vaginal, allowing for targeted and sustained release of drugs. Additionally, chitosan has been used in numerous biomedical applications, such as bone regeneration, cartilage tissue regeneration, cardiac tissue regeneration, corneal regeneration, periodontal tissue regeneration, and wound healing. Moreover, chitosan has also been utilized in gene delivery, bioimaging, vaccination, and cosmeceutical applications. Modified chitosan derivatives have been developed to improve their biocompatibility and enhance their properties, resulting in innovative materials with promising potentials in various biomedical applications. This article summarizes the recent findings on chitosan and its application in drug delivery and biomedical science.

Interaction of polyelectrolyte-shell cubosomes with serum albumin for triggering drug release in gastrointestinal cancer

Nano-structured and functionalized materials for encapsulation, transport, targeting and controlled release of drugs are of high interest to overcome low bioavailability in oral administration. We develop lipid-based cubosomes, which are surface-functionalized with biocompatible chitosan-N-arginine and alginate, displaying internal liquid crystalline structures. Polyelectrolyte-shell (PS) cubosomes have pH-responsive characteristics profitable for oral delivery. The obtained PScubosomes can strongly interact with serum albumin, a protein which is released in the stomach under gastric cancer conditions. An effective thermodynamic PScubosome-protein interaction was characterized at pH 2.0 and 7.4 by isothermal titration calorimetry at 37 °C. A high increment of the albumin conformation transition temperature was evidenced by differential scanning calorimetry upon incubation with PScubosomes. The performed structural studies by synchrotron small-angle X-ray scattering (SAXS) revealed essential alterations in the internal liquid crystalline topology of the nanocarriers including an Im3m to Pn3m transition and a reduction of the cubic lattice parameters. The PScubosome nanoparticle interaction with serum albumin, leading to inner structural changes in a range of temperatures, promoted the release of water from the cubosomal nanochannels. Altogether, the results revealed effective interactions of the PScubosomes with albumin under simulated gastrointestinal pH conditions and suggested promising nanocarrier characteristics for triggered oral drug release.

pH-Responsive and Mucoadhesive Nanoparticles for Enhanced Oral Insulin Delivery: The Effect of Hyaluronic Acid with Different Molecular Weights

Drug degradation at low pH and rapid clearance from intestinal absorption sites are the main factors limiting the development of oral macromolecular delivery systems. Based on the pH responsiveness and mucosal adhesion of hyaluronic acid (HA) and poly[2-(dimethylamino)ethyl methacrylate] (PDM), we prepared three HA–PDM nano-delivery systems loaded with insulin (INS) using three different molecular weights (MW) of HA (L, M, H), respectively. The three types of nanoparticles (L/H/M-HA–PDM–INS) had uniform particle sizes and negatively charged surfaces. The optimal drug loadings of the L-HA–PDM–INS, M-HA–PDM–INS, H-HA–PDM–INS were 8.69 ± 0.94%, 9.11 ± 1.03%, and 10.61 ± 1.16% (w/w), respectively. The structural characteristics of HA–PDM–INS were determined using FT-IR, and the effect of the MW of HA on the properties of HA–PDM–INS was investigated. The release of INS from H-HA–PDM–INS was 22.01 ± 3.84% at pH 1.2 and 63.23 ± 4.10% at pH 7.4. The protective ability of HA–PDM–INS with different MW against INS was verified by circular dichroism spectroscopy and protease resistance experiments. H-HA–PDM–INS retained 45.67 ± 5.03% INS at pH 1.2 at 2 h. The biocompatibility of HA–PDM–INS, regardless of the MW of HA, was demonstrated using CCK-8 and live–dead cell staining. Compared with the INS solution, the transport efficiencies of L-HA–PDM–INS, M-HA–PDM–INS, and H-HA–PDM–INS increased 4.16, 3.81, and 3.10 times, respectively. In vivo pharmacodynamic and pharmacokinetic studies were performed in diabetic rats following oral administration. H-HA–PDM–INS exhibited an effective hypoglycemic effect over a long period, with relative bioavailability of 14.62%. In conclusion, these simple, environmentally friendly, pH-responsive, and mucoadhesive nanoparticles have the potential for industrial development. This study provides preliminary data support for oral INS delivery.

Synthesis and Characterization of Innovative Microgels Based on Polyacrylic Acid and Microalgae Cell Wall and Their Potential as Antigen Delivery Vehicles

In this study, hybrid polyacrylic acid and Schizochytrium sp. microalgae (PAA/Schizo) microgels were synthesized by inverse emulsion assisted by ultrasound using the cell wall fraction as crosslinker. Physicochemical characterization of PAA/Schizo microgels revealed polymeric spherical particles (288 ± 39 nm) and were deemed stable and negatively charged. The produced microgels are not inherently toxic as cell viability was sustained above 80% when mice splenocytes were exposed to concentrations ranging 10-900 µg/mL. PAA/Schizo microgels were evaluated as antigen delivery nanovehicle by adsorbing bovine serum albumin (BSA); with a loading efficiency of 72% and loading capacity of 362 µg/mg. Overall, intranasally-immunized BALB/c mice showed null IgG or IgA responses against PAA/Schizo microgel-BSA, whereas soluble BSA induced significant humoral responses in systemic and mucosal compartments. Splenocytes proliferation assay upon BSA stimulus revealed positive CD4+ T cells-proliferation response in PAA/Schizo microgels-BSA group. Thus, PAA/Schizo microgels constitute functional antigen delivery vehicles of simple and ecofriendly synthesis. Moreover, the use of cell wall fraction as cross-linker agent provides an alternative use for the generation of high-value products using residual algae biomass from the oil industry. Our data suggests that the PAA/Schizo microgels are potential antigen delivery vehicles for immunotherapy development.

Therapy of Organophosphate Poisoning via Intranasal Administration of 2-PAM-Loaded Chitosomes

Chitosan-decorated liposomes were proposed for the first time for the intranasal delivery of acetylcholinesterase (AChE) reactivator pralidoxime chloride (2-PAM) to the brain as a therapy for organophosphorus compounds (OPs) poisoning. Firstly, the chitosome composition based on phospholipids, cholesterol, chitosans (Cs) of different molecular weights, and its arginine derivative was developed and optimized. The use of the polymer modification led to an increase in the encapsulation efficiency toward rhodamine B (RhB; ~85%) and 2-PAM (~60%) by 20% compared to conventional liposomes. The formation of monodispersed and stable nanosized particles with a hydrodynamic diameter of up to 130 nm was shown using dynamic light scattering. The addition of the polymers recharged the liposome surface (from -15 mV to +20 mV), which demonstrates the successful deposition of Cs on the vesicles. In vitro spectrophotometric analysis showed a slow release of substrates (RhB and 2-PAM) from the nanocontainers, while the concentration and Cs type did not significantly affect the chitosome permeability. Flow cytometry and fluorescence microscopy qualitatively and quantitatively demonstrated the penetration of the developed chitosomes into normal Chang liver and M-HeLa cervical cancer cells. At the final stage, the ability of the formulated 2-PAM to reactivate brain AChE was assessed in a model of paraoxon-induced poisoning in an in vivo test. Intranasal administration of 2-PAM-containing chitosomes allows it to reach the degree of enzyme reactivation up to 35 ± 4%.

Complexation of a Polypeptide-Polyelectrolytes Bioparticle as a Biomaterial of Antibacterial Activity

The development of biomaterials to enable application of antimicrobial peptides represents a strategy of high and current interest. In this study, a bioparticle was produced by the complexation between an antimicrobial polypeptide and the biocompatible and biodegradable polysaccharides chitosan-N-arginine and alginate, giving rise to a colloidal polyelectrolytic complex of pH-responsive properties. The inclusion of the polypeptide in the bioparticle structure largely increases the binding sites of complexation during the bioparticles production, leading to its effective incorporation. After lyophilization, detailed evaluation of colloidal structure of redispersed bioparticles evidenced nano or microparticles with size, polydispersity and zeta potential dependent on pH and ionic strength, and the dependence was not withdrawn with the polypeptide inclusion. Significant increase of pore edge tension in giant vesicles evidenced effective interaction of the polypeptide-bioparticle with lipid model membrane. Antibacterial activity against Aeromonas dhakensis was effective at 0.1% and equal for the isolated polypeptide and the same complexed in bioparticle, which opens perspectives to the composite material as an applicable antibacterial system.

Chitosan-nanoparticles effects on mucosal immunity: A systematic review

Nanoparticles-based treatments is of utmost importance for aquaculture. In this scenario, chitosan-based nanoparticles have been proposed due to the properties of chitosan, which include mucoadhesiveness. Nevertheless, pivotal parameters of chitosan, such as degree of acetylation and molecular weight, are commonly underestimated in the available literature despite the influence they seem to have on the properties of chitosan-based nanoparticles. In this systematic review, the immunomodulator capacity of chitosan nanoparticles used as mucosal vaccines on teleost fish has been evaluated paying special attention to the chitosan properties. Four databases were used for literature search, yielding 486 documents, from which 14 meet the inclusion criteria. Only 21% of the available studies reported properly chitosan properties, which should be improved in future works to generate reproducible data as well as valuable information. To the best of our knowledge, this work objectively compares for the first time, by quantifying the mg of chitosan/g of fish applied in each study, the chitosan nanoparticle preparation and doses applied to fish, as well as the effects of the treatments applied on fish immune status.

Mucoadhesive carriers for oral drug delivery

Among the various dosage forms, oral medicine has extensive benefits including ease of administration and patients' compliance, over injectable, suppositories, ocular and nasal. Despite of extensive demand and emerging advantages, over 50% of therapeutic molecules are not available in oral form due to their physicochemical properties. More importantly, most of the biologics, proteins, peptide, and large molecular drugs are mostly available in injectable form. Conventional oral drug delivery system has limitation such as degradation and lack of stability within stomach due to presence of highly acidic gastric fluid, hinders their therapeutic efficacy and demand more frequent and higher dosing. Hence, formulation for controlled, sustained, and targeted drug delivery, need to be designed with feasibility to target the specific region of gastrointestinal (GI) tract such as stomach, small intestine, intestine lymphatic, and colon is challenging. Among various oral delivery approaches, mucoadhesive vehicles are promising and has potential for improving oral drug retention and controlled absorption to treat local diseases within the GI tract, as well systemic diseases. This review provides the overview about the challenges and opportunities to design mucoadhesive formulation for oral delivery of therapeutics in a way to target the specific region of the GI tract. Finally, we have concluded with future perspective and potential of mucoadhesive formulations for oral local and systemic delivery.

Ivermectin: recent approaches in the design of novel veterinary and human medicines

Ivermectin (IVM) is a drug widely used in veterinary and human medicine for the management of parasitic diseases. Its repositioning potential has been recently considered for the treatment of different diseases, such as cancer and viral infections. However, IVM faces some limitations to its formulations due to its low water solubility and bioavailability, along with reports of drug resistance. In this sense, novel technological approaches have been explored to optimize its formulations and/or to develop innovative medicines. Therefore, this review discusses the strategies proposed in the last decade to improve the safety and efficacy of IVM and to explore its novel therapeutic applications. Among these technologies, the use of micro/nano-drug delivery systems is the most used approach, followed by long-acting formulations. In general, the development of these novel formulations seems to run side by side in veterinary and human health, showing a shared interface between the two areas. Although the technologies proposed indicate a promising future in the development of innovative dosage forms containing IVM, its safety and therapeutic targets must be further evaluated. Overall, these approaches comprise tailoring drug delivery profiles, decreasing the risks of developing drug resistance, and supporting the application of IVM for reaching different therapeutic targets.

Biodegradable Nanoparticles Prepared from Chitosan and Casein for Delivery of Bioactive Polysaccharides

Ophiopogon japonicus polysaccharides (OJPs) have great anti-inflammation and immunomodulatory abilities. However, the low bioavailability of OJPs reduces its applicability in the biomedical and pharmaceutical fields. Chitosan (CS) has excellent mucoadhesive properties and absorption-enhancing ability in oral administration. Casein hydrolysate (CL) has good interfacial diffusivity and emulsifying ability, and can interact with polysaccharides to form complexes combining the individual properties of both. Therefore, chitosan and casein hydrolysate are good candidates for developing nanoformulations for oral delivery. In this study, bioactive polysaccharides (OJPs), CS and CL, were combined to prepare CS/OJPs/CL co-assembled biodegradable nanoparticles. The interactions between polysaccharides (CS and OJPs) and peptide (CL) resulted in the formation of nanoparticles with an average particle size of 198 nm and high OJPs loading efficiency. The colloidal properties of the nanoparticles were pH-dependent, which were changed significantly in simulated digestive fluid at different pH values. OJPs released from the CS/OJPs/CL nanoparticles were greatly affected by pH and enzymatic degradation (trypsin and lysozyme). The nanoparticles were easily internalized by macrophages, thereby enhancing the OJPs’ inhibitory ability against Ni²⁺-induced cytotoxicity and LPS-induced nitric oxide production. This study demonstrates that prepared polysaccharide/protein co-assembled nanoparticles can be potential nanocarriers for the oral delivery of bioactive polysaccharides with anti-inflammatory functions.

Complexation behavior of carboxymethyl short-chain amylose and quaternized chitosan

The complexation of carboxymethyl short-chain amylose (CSA) and hydroxypropyl trimethyl ammonium chloride chitosan (HACC) and the stability of CSA/HACC nanocomplex were investigated. Resonance light scattering (RLS), turbidity, nanoparticle size and zeta potential analyses revealed that the complex coacervation occurred between CSA and HACC. The mass ratio and pH markedly influenced the complexation behavior; CSA with a higher degree of substitution (DS0.2) altered the complexation at a lower mass ratio and pH, increasing the turbidity and RLS intensity. The results of particle size and zeta potential analyses indicated that CSA/HACC complexes possessed the good pH and ionic strength stability. In addition to electrostatic interactions, hydrogen bonding and hydrophobic effects were also determined to be involved in the complexation process using thermal titration calorimetry (ITC). Additionally, the process was spontaneous, and CSA with a higher DS showed stronger complexation ability. These results may enable the understanding of polysaccharide complex behaviors.

A smart cauliflower-like carrier for astaxanthin delivery to relieve colon inflammation

As a fat-soluble carotenoid, astaxanthin has excellent antioxidant and anti-inflammation biological activities, but its poor biocompatibility and low stability limit application of astaxanthin in the food industry. In this study, cauliflower-like carriers (CCs) were constructed based on caseinate, chitosan-triphenylphosphonium (TPP) and sodium alginate through an electrostatic self-assembly method to improve the biocompatibility, stability and targeting transport properties of astaxanthin. The smart CCs showed pH-response release and mitochondrial targeted characteristics. In vitro studies demonstrated that the CCs could improve the internalization of astaxanthin, and significantly inhibited the excessive production of reactive oxygen species and the depolarization of mitochondrial membrane potential caused by oxidative stress. In vivo studies revealed that the astaxanthin-loaded CCs could effectively relieve the colitis induced by dextran sodium sulfate and protect the integrity of the colon tissue structure. The astaxanthin-loaded CCs could significantly inhibit the expression of inflammation factors such as interleukin-1β, interleukin-6, tumor necrosis factor alpha, cyclooxygenase-2, myeloperoxidase, inducible nitric oxide synthase, and nitric oxide. Moreover, the astaxanthin-loaded CCs could maintain the expression of zonula occludens-1, increase the abundance of Firmicutes and Lactobacillaceae in the intestine. In a word, the constructed astaxanthin delivery system provided a potential application for the oral uptake hydrophobic bio-activator in intervention of ulcerative colitis.

Efficient Treatment of Fish Intestinal Parasites Applying a Membrane-Penetrating Oral Drug Delivery Nanoparticle

Nanodelivery of drugs aims to ensure drug stability in the face of adverse biochemical conditions in the course of administration, concomitant with appropriate pharmacological action provided by delivery at the targeted site. In this study, the application potential of a nanoparticle produced with biopolymers chitosan-N-arginine and alginate as an oral drug delivery material is evaluated. Both macromolecules being weak polyelectrolytes, the nanoparticle presents strong thermodynamic interactions with a biological model membrane consisting of a charged lipid liposome bilayer, leading to membrane disruption and membrane penetration of the nanoparticles in ideal conditions of pH corresponding to the oral route. The powder form of the nanoparticle was obtained by lyophilization and with a high percentage of entrapment of the anthelmintic drug praziquantel. In vivo studies were conducted with oral administration to Corydoras schwartzi fish with high intensity of intestinal parasites infection. The in vivo experiments confirmed the mucoadhesive and revealed membrane-penetrating properties of the nanoparticle by translocating the parasite cyst, which provided target drug release and reduction of over 97% of the fish intestinal parasites. Thus, it was evidenced that the nanoparticle was effective in transporting and releasing the drug to the target, providing an efficient treatment.

High compliance and effective treatment of fish endoparasitic infections with oral drug delivery nanobioparticles: Safety of intestinal tissue and blood parameters

Parasite infections in fish require constant surveillance and strategies for efficient treatments which guarantee the fish health, their sale value and the non-propagation of pathogens in new environments. Fish treatments based on nanotechnology become of increasing interest since nanoparticles have been shown as efficient materials for optimizing administration of bioactives. In this study a chitosan derivative, alginate and praziquantel conjugated nanobioparticle of effective action for oral treatment of digenetic trematodes in highly infected Corydoras schwartzi was evaluated in terms of histological and hematological safety. The inherent absence of alterations in intestinal tissue and the reversible blood cells counting during a period up to 35 days showed the safety of the drug delivery nanobioparticles, which thus represent a promising strategy for effective applications in pathogens treatments by oral administration.

Cubosomal lipid nanoassemblies with pH-sensitive shells created by biopolymer complexes: A synchrotron SAXS study

We report a strategy for sustainable development of pH-responsive cubic liquid crystalline nanoparticles (cubosomes), in which the structure-defining lyotropic nonlamellar lipid and the eventually encapsulated guest molecules can be protected by pH-sensitive polyelectrolyte shells with mucoadhesive properties. Bulk non-lamellar phases as well as pH-responsive polyelectrolyte-modified nanocarriers were formed by spontaneous assembly of the nonlamellar lipid monoolein and two biopolymers tailored in nanocomplexes with pH-dependent net charge. The mesophase particles involved positively charged N-arginine-modified chitosan (CHarg) and negatively charged alginate (ALG) chains assembled at different biopolymer concentrations and charge ratios into a series of pH-responsive complexes. The roles of Pluronic F127 as a dispersing agent and a stabilizer of the nanoscale dispersions were examined. Synchrotron small-angle X-ray scattering (SAXS) investigations were performed at several N-arginine-modified chitosan/alginate ratios (CHarg/ALG with 10, 15 and 20 wt% ALG relative to CHarg) and varying pH values mimicking the pH conditions of the gastrointestinal route. The structural parameters characterizing the inner cubic liquid crystalline organizations of the nanocarriers were determined as well as the particle sizes and stability on storage. The surface charge variations, influencing the measured zeta-potentials, evidenced the inclusion of the CHarg/ALG biopolymer complexes into the lipid nanoassemblies. The polyelectrolyte shells rendered the hybrid cubosome nanocarriers pH-sensitive and influenced the swelling of their lipid-phase core as revealed by the acquired SAXS patterns. The pH-responsiveness and the mucoadhesive features of the cubosomal lipid/polyelectrolyte nanocomplexes may be of interest for in vivo drug delivery applications.

Preparation and optimization of controlled release nanoparticles containing cefixime using Central Composite design: An attempt to enrich its antimicrobial activity

BACKGROUND

Due to the increased resistance against existing antibiotics, research is essential to discover new and alternative ways to control infections induced by resistant pathogens.

OBJECTIVE

The goal of the current scrutinization was to enrich the dissolution rate and antibacterial property of cefixime (CEF) orally.

METHODS

To achieve the desired results, chitosan nanoparticles (NPs) containing CEF were fabricated using the ionic gelation method. Central Composite design has been applied to get the optimal formulation for the delivery of CEF. The effect of three variables such as the concentration of chitosan, tripolyphosphate, and tween 80 on the characteristics of NPs was evaluated.

RESULTS

The optimized NPs were a relatively monodispersed size distribution with an average diameter of 193 nm and a zeta potential of about 11 mV. The scanning tunneling microscope confirmed the size of NPs. The surface morphology of NPs was observed by scanning electron microscopy. The calorimetric analysis indicated the amorphous state of cefixime in the formulation. The dissolution rate of NPs in aqueous media was acceptable and the model of release kinetic for CEF from NPs followed the Peppas model. The potency of CEF in NPs against various types of bacteria was hopefully efficient. The ex- vivo release study demonstrated higher penetration of NPs from the rat intestine compared to free drug. The cell culture study showed the safety of the optimized formulation.

CONCLUSION

It was concluded that CLN could be considered as a prospering system for the controlled delivery of CEF with advantaging its antibacterial effectiveness.

Starch modified alginate nanoparticles for drug delivery application

Natural polymers have been widely studied as vehicles that have gained much interest in the encapsulation and delivery of drugs and bioactive molecules. In this study, we developed starch-modified alginate nanoparticles using a green facile technique for drug delivery application. The potential of the prepared nanoparticles for controlled drug delivery applications is demonstrated using theophylline and bovine serum albumin as model drugs. The nanoparticles possessed the encapsulation efficiency of 60 to 75%. The results of in vitro drug release studies showed the pH dependent characteristics of the prepared nanoparticles. In vitro cytotoxicity test revealed the biocompatibility of the developed nanoparticles against L929 fibroblast cell lines. The in vitro cellular uptake of nanoparticles was visualized in L929 fibroblast cells using fluorescent microscopy. The preliminary investigation suggests the developed nanoparticle is a promising candidate for drug delivery application.

Safety of oral administration of high doses of ivermectin by means of biocompatible polyelectrolytes formulation

The FDA-approved drug ivermectin is applied for treatments of onchocerciasis and lymphatic filariasis. The anti-cancer and anti-viral activities have been demonstrated stressing possibilities for the drug repurposing and therefore new information on high dosage safety is on demand. We analyzed in vivo tissue responses for high doses of ivermectin using Corydoras fish as animal model. We made intestinal histology and hematologic assays after oral administration of ivermectin transported with polyelectrolytes formulation. Histology showed any apparent damage of intestinal tissues at 0.22–170 mg of ivermectin/kg body weight. Immunofluorescence evidenced delocalization of Myosin-Vb at enterocytes only for the higher dose. Hematology parameters showed random variations after 7 days from administration, but a later apparent recover after 14 and 21 days. The study evaluated the potential of high doses of oral administration of ivermectin formulation, which could be an alternative with benefits in high compliance therapies.

Modulating properties of polysaccharides nanocomplexes from enzymatic hydrolysis of chitosan

Synthesis of nanocomplexes is a simple and low-cost technique for the production of encapsulation systems aiming industrial applications, based on the interaction of at least two oppositely charged molecules. Gellan gum (anionic) is a water-soluble biopolymer resistant to stomach pH conditions, therefore an interesting alternative as an encapsulating matrix. Chitosan (cationic) is also widely used due to its biocompatibility and mucoadhesive properties, although its low water solubility is an important step to be overcome for the production of the complexes. To improve this property, many techniques have been employed, but most of them use unsustainable techniques and chemical agents. The enzymatic hydrolysis of chitosan using proteases emerges as an alternative to these drawbacks and, therefore, this study aimed to evaluate the electrostatic nanocomplexation of native (C) or hydrolyzed (HC) chitosan (by porcine pepsin protease) with gellan gum (G). Polysaccharides and nanocomplexes formed with different G:C or G:HC ratio were evaluated by zeta potential measurements, particle size distribution, X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Transmission Electron Microscopy (STEM), intrinsic viscosity and turbidity analyses. Chitosan hydrolysis allowed the formation of a smaller (445.3 nm in pH 4.5) and more soluble structure (3 kDa), which positively influenced the formation of the complexes. The ratios G:HC of 7:3 and 8:2 formed complexes with lower values of zeta potential (13.9 mV and -5.0 mV, respectively), particle size (635.8 nm and 533.6 nm, respectively) and polydispersity (0.28 and 0.23) compared to complexes formed with native chitosan. Overall, our results show that enzymatic hydrolysis of chitosan favored the formation of electrostatic complexes with reduced size and low polydispersity, which can be used as efficient encapsulating matrices for improved targeted delivery and controlled release of bioactive compounds.

Advances in the Design of pH-Sensitive Cubosome Liquid Crystalline Nanocarriers for Drug Delivery Applications

Nanostructure bicontinuous cubic phase self-assembled materials are receiving expanding applications as biocompatible delivery systems in various therapeutic fields. The functionalization of cubosome, spongosome, hexosome and liposome nanocarriers by pH-sensitive lipids and/or pH-sensitive polymer shells offers new opportunities for oral and topical drug delivery towards a new generation of cancer therapies. The electrochemical behavior of drug compounds may favor pH-triggered drug release as well. Here, we highlight recent investigations, which explore the phase behavior of mixed nonlamellar lipid/fatty acid or phospholipid systems for the design of pH-responsive and mucoadhesive drug delivery systems with sustained-release properties. X-ray diffraction and small-angle X-ray scattering (SAXS) techniques are widely used in the development of innovative delivery assemblies through detailed structural analyses of multiple amphiphilic compositions from the lipid/co-lipid/water phase diagrams. pH-responsive nanoscale materials and nanoparticles are required for challenging therapeutic applications such as oral delivery of therapeutic proteins and peptides as well as of poorly water-soluble substances. Perspective nanomedicine developments with smart cubosome nanocarriers may exploit compositions elaborated to overcome the intestinal obstacles, dual-drug loaded pH-sensitive liquid crystalline architectures aiming at enhanced therapeutic efficacy, as well as composite (lipid/polyelectrolyte) types of mucoadhesive controlled release colloidal cubosomal formulations for the improvement of the drugs' bioavailability.