Chitosan-alginate microparticles as a protein carrier

Chitosan-alginate microcapsules: A strategy for improving stability and antibacterial potential of bovine Lactoferrin

Lactoferrin, a multifunctional glycoprotein with significant biological properties, presents significant potential for the prevention and treatment of infectious diseases. However, the effectiveness of oral Lactoferrin is limited by its susceptibility to degradation in harsh stomach conditions, reducing its bioavailability and therapeutic efficacy. To address this challenge, this study employs Chitosan/Alginate microparticles to enhance Lactoferrin stability and antibacterial activity. Microparticles were synthesized through external ionic gelation and thoroughly characterized. Chitosan/Alginate microparticles were significantly smaller than Alginate microparticles, with a high loading efficiency of 93.65 %. Fourier transform infrared (FT-IR) spectroscopy confirmed the successful incorporation of Lactoferrin. Release studies demonstrated minimal Lactoferrin release in simulated gastric fluid, while a controlled release was observed in simulated intestinal fluid. Notably encapsulated Lactoferrin retained its structural integrity after exposure to simulated gastrointestinal conditions. Antibacterial assay against Escherichia coli showed that Chitosan/Alginate microcapsules maintain Lactoferrin antibacterial activity after its passage through simulated gastrointestinal conditions. Furthermore, FT-IR spectroscopy and zeta-potential analysis provided novel insights into the mechanism of Lactoferrin's interaction with bacterial LPS, highlighting its ability to destabilize bacterial membrane of this Escherichia coli strain. These findings underscore the Chitosan/Alginate system as a promising strategy for enhancing the therapeutic potential of Lactoferrin.

Gp85 protein encapsulated by alginate-chitosan composite microspheres induced strong immunogenicity against avian leukosis virus in chicken

Introduction

Avian leukosis, a viral disease affecting birds such as chickens, presents significant challenges in poultry farming due to tumor formation, decreased egg production, and increased mortality. Despite the absence of a commercial vaccine, avian leukosis virus (ALV) infections have been extensively documented, resulting in substantial economic losses in the poultry industry. This study aimed to develop alginate-chitosan composite microspheres loaded with ALV-J Gp85 protein (referred to as aCHP-gp85) as a potential vaccine candidate.

Methods

Sodium alginate and chitosan were utilized as encapsulating materials, with the ALV-J Gp85 protein serving as the active ingredient. The study involved 45 specific pathogen-free (SPF) chickens to evaluate the immunological effectiveness of aCHP-gp85 compared to a traditional Freund adjuvant-gp85 vaccine (Freund-gp85). Two rounds of vaccination were administered, and antibody levels, mRNA expression of immune markers, splenic lymphocyte proliferation, and immune response were assessed. An animal challenge experiment was conducted to evaluate the vaccine's efficacy in reducing ALV-J virus presence and improving clinical conditions.

Results

The results demonstrated that aCHP-gp85 induced a significant and sustained increase in antibody levels compared to Freund-gp85, with the elevated response lasting for 84 days. Furthermore, aCHP-gp85 significantly upregulated mRNA expression levels of key immune markers, notably TNF-α and IFN-γ. The application of ALV-J Gp85 protein within the aCHP-gp85 group led to a significant increase in splenic lymphocyte proliferation and immune response. In the animal challenge experiment, aCHP-gp85 effectively reduced ALV-J virus presence and improved clinical conditions compared to other groups, with no significant pathological changes observed.

Discussion

The findings suggest that aCHP-gp85 elicits a strong and prolonged immune response compared to Freund-gp85, indicating its potential as an innovative ALV-J vaccine candidate. These results provide valuable insights for addressing avian leukosis in the poultry industry, both academically and practically.

Multi-layer encapsulation of pumpkin (Cucurbita maxima L.) seed protein hydrolysate and investigating its release and antioxidant activity in simulated gastrointestinal digestion

Because of their high protein content, easy access and low cost, pumpkin seeds are a valuable raw material for the preparation of antioxidant protein hydrolysates. Micro-coating is an effective method to protect bioactive compounds against destruction. In order to strengthen the alginate hydrogel network loaded with pumpkin seed protein hydrolysate (PSPH), CMC was added as part of its formulation in the first step, and chitosan coating was used in the second step. Then, swelling amount, release in the simulated gastrointestinal environment (SGI), antioxidant activity after SGI, Fourier transform infrared spectroscopy (FTIR), zeta potential, dynamic light scattering (DLS), polydispersity index (PDI) and scanning electron microscopy (SEM) of the samples were evaluated. The results showed that, the swelling amount of the chitosan-alginate hydrogel was lower than the chitosan-alginate-CMC sample, and with the increase in chitosan concentration, the swelling amount decreased. The release amount in the chitosan-alginate sample was higher than that in the chitosan-alginate-CMC sample, and with the increase in chitosan concentration, the release rate decreased. Also, the amount of release increased with the passage of time. The highest antioxidant activity belonged to the chitosan-alginate sample in SGI, and it increased with increasing the chitosan concentration. All findings demonstrated that the use of multi-component hybrid systems is a useful method for the protection of bioactive compounds against destruction, their antioxidant activities and their release behavior.

Ozonated Sunflower Oil Embedded within Spray-Dried Chitosan Microspheres Cross-Linked with Azelaic Acid as a Multicomponent Solid Form for Broad-Spectrum and Long-Lasting Antimicrobial Activity

Multicomponent solid forms for the combined delivery of antimicrobials can improve formulation performance, especially for poorly soluble drugs, by enabling the modified release of the active ingredients to better meet therapeutic needs. Chitosan microspheres incorporating ozonated sunflower oil were prepared by a spray-drying method and using azelaic acid as a biocompatible cross-linker to improve the long time frame. Two methods were used to incorporate ozonated oil into microspheres during the atomization process: one based on the use of a surfactant to emulsify the oil and another using mesoporous silica as an oil absorbent. The encapsulation efficiency of the ozonated oil was evaluated by measuring the peroxide value in the microspheres, which showed an efficiency of 75.5-82.1%. The morphological aspects; particle size distribution; zeta potential; swelling; degradation time; and thermal, crystallographic and spectroscopic properties of the microspheres were analyzed. Azelaic acid release and peroxide formation over time were followed in in vitro analyses, which showed that ozonated oil embedded within chitosan microspheres cross-linked with azelaic acid is a valid system to obtain a sustained release of antimicrobials. In vitro tests showed that the microspheres exhibit synergistic antimicrobial activity against P. aeruginosa, E. coli, S. aureus, C. albicans and A. brasiliensis. This makes them ideal for use in the development of biomedical devices that require broad-spectrum and prolonged antimicrobial activity.

Microencapsulation of Piscirickettsia salmonis Antigens for Fish Oral Immunization: Optimization and Stability Studies

The development of fish oral vaccines is of great interest to the aquaculture industry due to the possibility of rapid vaccination of a large number of animals at reduced cost. In a previous study, we evaluated the effect of alginate-encapsulated Piscirickettsia salmonis antigens (AEPSA) incorporated in feed, effectively enhancing the immune response in Atlantic salmon (Salmo salar). In this study, we seek to characterize AEPSA produced by ionic gelation using an aerodynamically assisted jetting (AAJ) system, to optimize microencapsulation efficiency (EE%), to assess microparticle stability against environmental (pH, salinity and temperature) and gastrointestinal conditions, and to evaluate microparticle incorporation in fish feed pellets through micro-CT-scanning. The AAJ system was effective in obtaining small microparticles (d < 20 μm) with a high EE% (97.92%). Environmental conditions (pH, salinity and temperature) generated instability in the microparticles, triggering protein release. 62.42% of the protein content was delivered at the intestinal level after in vitro digestion. Finally, micro-CT-scanning images confirmed microparticle incorporation in fish feed pellets. In conclusion, the AAJ system is effective at encapsulating P. salmonis antigens in alginate with a high EE% and a size small enough to be incorporated in fish feed and produce an oral vaccine.

Preparation and Characteristics of Alginate Microparticles for Food, Pharmaceutical and Cosmetic Applications

Alginates are the most widely used natural polymers in the pharmaceutical, food and cosmetic industries. Usually, they are applied as a thickening, gel-forming and stabilizing agent. Moreover, the alginate-based formulations such as matrices, membranes, nanospheres or microcapsules are often used as delivery systems. Alginate microparticles (AMP) are biocompatible, biodegradable and nontoxic carriers, applied to encapsulate hydrophilic active substances, including probiotics. Here, we report the methods most frequently used for AMP production and encapsulation of different actives. The technological parameters important in the process of AMP preparation, such as alginate concentration, the type and concentration of other reagents (cross-linking agents, oils, emulsifiers and pH regulators), agitation speed or cross-linking time, are reviewed. Furthermore, the advantages and disadvantages of alginate microparticles as delivery systems are discussed, and an overview of the active ingredients enclosed in the alginate carriers are presented.

Oral Bioavailability Enhancement of Melanin Concentrating Hormone, Development and In Vitro Pharmaceutical Assessment of Novel Delivery Systems

The rapid progress in biotechnology over the past few decades has accelerated the large-scale production of therapeutic peptides and proteins, making them available in medical practice. However, injections are the most common method of administration; these procedures might lead to inconvenience. Non-invasive medications, such as oral administration of bio-compounds, can reduce or eliminate pain and increase safety. The aim of this project was to develop and characterize novel melanin concentrating hormone (MCH) formulations for oral administration. As a drug delivery system, penetration enhancer combined alginate beads were formulated and characterized. The combination of alginate carriers with amphiphilic surfactants has not been described yet. Due to biosafety having high priority in the case of novel pharmaceutical formulations, the biocompatibility of selected auxiliary materials and their combinations was evaluated using different in vitro methods. Excipients were selected according to the performed toxicity measurements. Besides the cell viability tests, physical properties and complex bioavailability assessments were performed as well. Our results suggest that alginate beads are able to protect melanin concentrating hormones. It has been also demonstrated that penetration enhancer combined alginate beads might play a key role in bioavailability improvement. These formulations were found to be promising tools for oral peptide delivery. Applied excipients and the performed delivery systems are safe and highly tolerable; thus, they can improve patients’ experience and promote adherence.

Oral colon-targeting core-shell microparticles loading curcumin for enhanced ulcerative colitis alleviating efficacy

Background

The oral colon-targeting drug delivery vehicle is vital for the efficient application of curcumin (Cur) in ulcerative colitis (UC) treatment because of its lipophilicity and instability in the gastrointestinal tract.

Methods

The core–shell microparticle (MP) system composed of eco-friendly materials, zein and shellac, was fabricated using a coaxial electrospray technique. In this manner, Cur was loaded in the zein core, with shellac shell coating on it. The colon-targeting efficiency and accumulation capacity of shellac@Cur/zein MPs were evaluated using a fluorescence imaging test. The treatment effects of free Cur, Cur/zein MPs, and shellac@Cur/zein MPs in acute experimental colitis were compared.

Results

With the process parameters optimized, shellac@Cur/zein MPs were facilely fabricated with a stable cone-jet mode, exhibiting standard spherical shape, uniform size distribution (2.84 ± 0.15 µm), and high encapsulation efficiency (95.97% ± 3.51%). Particularly, with the protection of shellac@zein MPs, Cur exhibited sustained drug release in the simulated gastrointestinal tract. Additionally, the in vivo fluorescence imaging test indicated that the cargo loaded in shellac@zein MPs improves the colon-targeting efficiency and accumulation capacity at the colonitis site. More importantly, compared with either free Cur or Cur/zein MPs, the continuous oral administration of shellac@Cur/zein MPs for a week could efficiently inhibit inflammation in acute experimental colitis.

Conclusion

The shellac@Cur/zein MPs would act as an effective oral drug delivery system for UC management.

Recent Advances and Challenges in Nanodelivery Systems for Antimicrobial Peptides (AMPs)

Antimicrobial peptides (AMPs) can be used as alternative therapeutic agents to traditional antibiotics. These peptides have abundant natural template sources and can be isolated from animals, plants, and microorganisms. They are amphiphilic and mostly net positively charged, and they have a broad-spectrum inhibitory effect on bacteria, fungi, and viruses. AMPs possess significant rapid killing effects and do not interact with specific receptors on bacterial surfaces. As a result, drug resistance is rarely observed with treatments. AMPs, however, have some operational problems, such as a susceptibility to enzymatic (protease) degradation, toxicity in vivo, and unclear pharmacokinetics. However, nanodelivery systems loaded with AMPs provide a safe mechanism of packaging such peptides before they exert their antimicrobial actions, facilitate targeted delivery to the sites of infection, and control the release rate of peptides and reduce their toxic side effects. However, nanodelivery systems using AMPs are at an early stage of development and are still in the laboratory phase of development. There are also some challenges in incorporating AMPs into nanodelivery systems. Herein, an insight into the nanotechnology challenges in delivering AMPs, current advances, and remaining technological challenges are discussed in depth.

Encapsulation of Synthesized Plant Growth Regulator Based on Copper(II) Complex in Chitosan/Alginate Microcapsules

A new copper complex, trans-diaqua-trans-bis [1-hydroxy-1,2-di (methoxycarbonyl) ethenato] copper (abbreviation Cu(II) complex), was synthesized and its plant growth regulation properties were investigated. The results show a sharp dependence of growth regulation activity of the Cu(II) complex on the type of culture and its concentration. New plant growth regulator accelerated the development of the corn root system (the increase in both length and weight) but showed a smaller effect on the development of the wheat and barley root systems. Stimulation of corn growth decreased with increasing Cu(II) complex concentration from 0.0001% to 0.01% (inhibition at high concentrations-0.01%). The development of corn stems was also accelerated but to a lesser extent. Chitosan-coated calcium alginate microcapsules suitable for delivery of Cu(II) complex to plants were prepared and characterized. Analysis of the FTIR spectrum showed that complex molecular interactions between functional groups of microcapsule constituents include mainly electrostatic interactions and hydrogen bonds. Microcapsules surface exhibits a soft granular surface structure with substructures consisting of abundant smaller particles with reduced surface roughness. Release profile analysis showed Fickian diffusion is the rate-controlling mechanism of Cu(II) complex releasing. The obtained results give new insights into the complexity of the interaction between the Cu(II) complex and microcapsule formulation constituents, which can be of great help in accelerating product development for the application in agriculture.

Implementation and in vitro characterization of calcium-free in situ gelling oral reconstituted suspension for potential overweight treatment

In this work, oral granules that were easily dissolved in aqueous dispersion, were prepared. These oral suspensions were formulated with sodium alginate (AlgNa), chitosan (CHI) and sodium carboxymethylcellulose (CMC Na). The gels were formulated by pouring the suspensions into 150 ml of simulated gastric fluid (SGF) pH 1.2 at 37° C. The in-situ gelling mechanism was based on the ionization states of the three biopolymers as a function of the pH of the medium. Fourier transform infrared analysis of gels confirmed the interactions between alginate and chitosan. According to the scanning electron microscopy analysis, the gels were characterized by a firm and homogeneous structure. The obtained values of the elastic storage modulus, G', varied between 10 1   and 10 7 Pa. The eliminated volume of the unabsorbed liquid by the gels fluctuated between 25% and 55% of the total liquid volume. The quality of the gels was improved when a maximum concentration of alginate ( 4   g / 100   ml ) , a minimum concentration of chitosan ( 0.5   g / 100   ml ) and a maximum amount of carboxymethylcellulose ( 4   g / 100   ml ) were used. The value of their elastic modulus, G' was around 10 5 Pa and the residual unabsorbed volume of the liquid was 25% of the total liquid volume. According to the obtained results, the prepared gels could induce a feeling of fullness by stimulating the gastric distension and they could potentially be applied as anti-obesity medication.

Preparation of Hybrid Alginate-Chitosan Aerogel as Potential Carriers for Pulmonary Drug Delivery

This study aims to prepare hybrid chitosan-alginate aerogel microparticles without using additional ionic crosslinker as a possible pulmonary drug delivery system. The microparticles were prepared using the emulsion gelation method. The effect of the mixing order of the biopolymer within the emulsion and the surfactant used on final particle properties were investigated. Physicochemical characterizations were performed to evaluate particle size, density, morphology, surface area, surface charge, and the crystallinity of the preparation. The developed preparation was evaluated for its acute toxicity in adult male Sprague-Dawley rats. Measurements of zeta potential suggest that the surface charge depends mainly on the surfactant type while the order of biopolymer mixing has less impact on the surface charge. Chitosan amphiphilic properties changed the hydrophilic-lipophilic balance (HLB) of the emulsifying agents. The specific surface area of the prepared microparticles was in the range of (29.36-86.20) m²/g with a mesoporous pore size of (12.48-13.38) nm and pore volume of (0.09-0.29) cm³/g. The calculated aerodynamic diameter of the prepared particles was in the range of (0.17-2.29 µm). Toxicity studies showed that alginate-chitosan carrier developed herein caused mild lung inflammation with some renal and hepatic toxicities.

Design and in vitro antibiofilm activity of propolis diffusion-controlled biopolymers

In this study, a novel pH-sensitive hydrogel beads that is based on gelatin/sodium alginate/chitosan (GEL/SA/CS) loaded with propolis ethanolic extracts (PE) were synthesized. The swelling behavior of GEL/SA/CS hydrogel beads was studied in different pH solutions and compared with unloaded CS (GEL/SA) hydrogel beads. The in vitro release studies have been revealed using four different pH (1.3, 5.0, 6.0, and 6.8), a saliva environment (pH 6.8), a simulated gastric fluid (SGF) (pH 1.3), and a simulated intestinal fluid (SIF) (pH 6.8) to simulate the physiological conditions in gastrointestinal (GI) tract. Propolis-loaded hydrogel beads were found to be stable at pH 1.3, 5.0, 6.0, simulated saliva, SGF, and SIF mediums, whereas the beads lose their stability at pH 6.8 buffer solution. Tested microorganisms displayed greater sensitivity to PE-loaded hydrogel beads compared with pure propolis. Contrary to antimicrobial activity results, antibiofilm activity results of PE-loaded GEL/SA and GEL/SA/CS hydrogel beads were found at low levels. According to the obtained results, the propolis-loaded GEL/SA/CS hydrogel beads synthesized within this study can be used in the treatment of GI tract diseases such as oral mucositis, gastric ulcer, ulcerative colitis, and GI cancer, as controlled releasing carriers of propolis.

Development of Microspheres Based on Thiol-Modified Sodium Alginate for Intestinal-Targeted Drug Delivery

Bioactive peptide drugs are mostly delivered by parenteral administration, which brings great pain and risks to patients. Oral administration is an acceptable alternative form. However, peptide drugs are extremely sensitive to the strong acidic environment in the stomach after oral administration. They would be degraded by pepsin and trypsin in the gastrointestinal tract. Herein, we present microspheres for intestinal-targeted peptides drug delivery through oral administration. Sodium alginate was reacted with l-cysteine to bring it into thiol groups. Then sodium alginate-l-cysteine conjugates were mixed with native sodium alginate and emulsified by an improved method. Ca²⁺ was used to fix the emulsion to get the microspheres. Bovine serum albumin was used as the simulating drug to assess the feasibility of microspheres as intestinal delivery carriers. The results showed that the microspheres exhibited spherical properties and narrow size distribution. The drug-loading capacity of microspheres was not compromised after thiol-modification. It is interesting that the microspheres can maintain structural integrity and hold drugs in the strong acidic environment in the stomach. Conversely, the microspheres presented sustained intestinal-targeted drugs release ability as expected. Moreover, thiol-modification further improved the adherence ability of microspheres on the inner walls of the small intestine, which is good for enhancing drug permeability. In sum, the microspheres based on thiol-modified sodium alginate have promising applications as intestinal-targeted macromolecular drug carriers.

Entrapment of LTB protein in alginate nanoparticles protects against Enterotoxigenic Escherichia coli

Vaccine delivery vehicles are just as important in vaccine efficiency. Through the progress in nanotechnology, various nanoparticles have been evaluated as carriers for these substances. Among them, alginate nanoparticles are a good choice because of their biodegradability, biocompatibility, ease of production, etc. In this study, feasibility of alginate nanoparticles (NPs) such as recombinant LTB from Enterotoxigenic Escherichia coli (ETEC) carrier was investigated. To do this, the eltb gene was cloned and expressed in E. coli BL21 (DE3) host cells, and a Ni-NTA column purified the protein. NPs were achieved through ion gelation method in the presence of LTB protein and CaCl₂ as the cross-Linker and NPs were characterized physicochemically. Balb/C mice groups were immunized with LTB-entrapped NPs or LTB with adjuvant and immunogenicity was assessed by evaluating IgG titer. Finally, the neutralization of antibodies was evaluated by GM1 binding and loop assays. LTB protein was expressed and efficiently entrapped into the alginate NPs. The size of NPs was less than 50 nm, and entrapment efficiency was 80%. Western blotting showed maintenance of the molecular weight and antigenicity of the released protein from NPs. Administration of LTB-entrapped NPs stimulated antibody responses in immunized mice. Immunization induced protection against LT toxin of ETEC in ileal loops and inhibits enterotoxin binding to GM1-gangliosides. Alginate NPs are also appropriate vehicle for antigen delivery purpose. Moreover because of their astonishing properties, they have the potential to serve as an adjuvant.

Coating Matters: Review on Colloidal Stability of Nanoparticles with Biocompatible Coatings in Biological Media, Living Cells and Organisms

Within the last two decades, the field of nanomedicine has not developed as successfully as has widely been hoped for. The main reason for this is the immense complexity of the biological systems, including the physico-chemical properties of the biological fluids as well as the biochemistry and the physiology of living systems. The nanoparticles' physicochemical properties are also highly important. These differ profoundly from those of freshly synthesized particles when applied in biological/living systems as recent research in this field reveals. The physico-chemical properties of nanoparticles are predefined by their structural and functional design (core and coating material) and are highly affected by their interaction with the environment (temperature, pH, salt, proteins, cells). Since the coating material is the first part of the particle to come in contact with the environment, it does not only provide biocompatibility, but also defines the behavior (e.g. colloidal stability) and the fate (degradation, excretion, accumulation) of nanoparticles in the living systems. Hence, the coating matters, particularly for a nanoparticle system for biomedical applications, which has to fulfill its task in the complex environment of biological fluids, cells and organisms. In this review, we evaluate the performance of different coating materials for nanoparticles concerning their ability to provide colloidal stability in biological media and living systems.

Microparticles, microcapsules and microspheres: A review of recent developments and prospects for oral delivery of insulin

Diabetes mellitus is a chronic metabolic health disease affecting the homeostasis of blood sugar levels. However, subcutaneous injection of insulin can lead to patient non-compliance, discomfort, pain and local infection. Sub-micron sized drug delivery systems have gained attention in oral delivery of insulin for diabetes treatment. In most of the recent literature, the terms "microparticles" and "nanoparticle" refer to particles where the dimensions of the particle are measured in micrometers and nanometers respectively. For instance, insulin-loaded particles are defined as microparticles with size larger than 1 μm by most of the research groups. The size difference between nanoparticles and microparticles proffers numerous effects on the drug loading efficiency, aggregation, permeability across the biological membranes, cell entry and tissue retention. For instance, microparticulate drug delivery systems have demonstrated a number of advantages including protective effect against enzymatic degradation, enhancement of peptide stability, site-specific and controlled drug release. Compared to nanoparticulate drug delivery systems, microparticulate formulations can facilitate oral absorption of insulin by paracellular, transcellular and lymphatic routes. In this article, we review the current status of microparticles, microcapsules and microspheres for oral administration of insulin. A number of novel techniques including layer-by-layer coating, self-polymerisation of shell, nanocomposite microparticulate drug delivery system seem to be promising for enhancing the oral bioavailability of insulin. This review draws several conclusions for future directions and challenges to be addressed for optimising the properties of microparticulate drug formulations and enhancing their hypoglycaemic effects.

Microparticles as controlled drug delivery carrier for the treatment of ulcerative colitis: A brief review

Ulcerative colitis is the chronic relapsing multifactorial gastrointestinal inflammatory bowel disease, which is characterized by bloody or mucus diarrhea, tenesmus, bowel dystension, anemia. The annual incidence of ulcerative colitis in Asia, North America and Europe was found to be 6.3, 19.2 and 24.3 per 100,000 person-years. The major challenge in the treatment of ulcerative colitis is appropriate local targeting and drug related side-effects. To overcome these challenges, microparticulate systems seem to be a promising approach for controlled and sustained drug release after oral administration. The main goal of this article is to explore the role of microparticles in ulcerative colitis for the appropriate targeting of drugs to colon. There are different approaches which have been studied over the last decade, including prodrugs, polymeric approach, time released system, pH sensitive system, which show the site specific drug delivery to colon. Among these approaches, microparticulate drug delivery system has been gaining an immense importance for local targeting of drug to colon at a controlled and sustained rate. Combined approaches such as pH dependent and time dependent system provide the maximum release of drug into colon via oral route. This article embraces briefly about pathophysiology, challenges and polymeric approaches mainly multiparticulate systems for site specific drug delivery to colon in sustained and controlled manner so that drug related side-effects by reducing dosage frequency can be minimized.

Polymeric protective agents for nanoparticles in drug delivery and targeting

Surface modification/functionalization of nanoparticles (NPs) using polymeric protective agents is an issue of great importance and actuality for drug delivery and targeting. Improving the blood circulation half-life of surface-protected nanocarriers is closely related to the elimination of main biological barriers and limiting factors (protein absorption and opsonization), due to the phagocytic activity of reticuloendothelial system. For passive or active targeted delivery, in biomedical area, surface-functionalized NPs with tissue-recognition ligands were designed and optimized as a result of modern research techniques. Also, multi-functionalized nanostructures are characterized by enhanced bioavailability, efficacy, targeted localization, active cellular uptake, and low side effects. Surface-protected NPs are obtained from biocompatible, biodegradable and less toxic natural polymers (dextran, β-cyclodextrin, chitosan, hyaluronic acid, heparin, gelatin) or synthetic polymers, such as poly(lactic acid), poly(lactic-co-glycolic) acid, poly(ε-caprolactone) and poly(alkyl cyanoacrylates). PEGylation is one of the most important functionalization methods providing steric stabilization, long circulating and 'stealth' properties for both polymeric and inorganic-based nanosystems. In addition, for their antimicrobial, antiviral and antitumor effects, cutting-edge researches in the field of pharmaceutical nanobiotechnology highlighted the importance of noble metal (platinum, gold, silver) NPs decorated with biopolymers.

Preparation of nanosized coacervates of positive and negative starch derivatives intended for pulmonary delivery of proteins

Use of charged starch-derivatives as nanoscaled protein carriers and their in vitro evaluation.

Design and characterization of chitosan-based composite particles with tunable interfacial properties

Composite nano-microparticles were prepared in aqueous solution that contain chitosan or modified (carboxymethyl) chitosan with polyanion species such as alginate or tripolyphosphate, respectively. Several types of particles were prepared and characterized by (1)H/(31)P NMR spectroscopy, IR spectroscopy, and DLS. According to DLS, the particle size was observed to increase as the concentration of the aqueous urea solution increased. The average size and polydispersity index (in parentheses) vary and are reported for the chitosan-based particles from 243.0 ± 1 nm (0.28) to 424 ± 14 nm (0.33), according to DLS measurements at ambient conditions. Thus, the particles are herein referred to as nano-microparticles (NMPs) due to the relative size range. The stability of the NMPs is related to the particle composition and the aqueous solution conditions, as evidenced by variable NMP stability on the order of two weeks or more at different ionic strength.

Alginate nanoparticles as a promising adjuvant and vaccine delivery system

During last decades, diphtheria has remained as a serious disease that still outbreaks and can occur worldwide. Recently, new vaccine delivery systems have been developed by using the biodegradable and biocompatible polymers such as alginate. Alginate nanoparticles as a carrier with adjuvant and prolong release properties that enhance the immunogenicity of vaccines. In this study diphtheria toxoid loaded nanoparticles were prepared by ionic gelation technique and characterized with respect to size, zeta potential, morphology, encapsulation efficiency, release profile, and immunogenicity. Appropriate parameters (calcium chloride and sodium alginate concentration, homogenization rate and homogenization time) redounded to the formation of suitable nanoparticles with a mean diameter of 70±0.5 nm. The loading studies of the nanoparticles resulted in high loading capacities (>90%) and subsequent release studies showed prolong profile. The stability and antigenicity of toxoid were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and ouchterlony test and proved that the encapsulation process did not affect the antigenic integrity and activity. Guinea pigs immunized with the diphtheria toxoid-loaded alginate nanoparticles showed highest humoral immune response than conventional vaccine. It is concluded that, with regard to the desirable properties of nanoparticles and high immunogenicity, alginate nanoparticles could be considered as a new promising vaccine delivery and adjuvant system.

Polarization optical-histochemical characterization and supramolecular structure of carbohydrate fibrils

Topo-optical staining reactions were used to investigate the structures of bacterial cellulose, insect chitosan and alginic acid from brown algae. Polysaccharide complexes, glycosaminoglycans and sulfate groups were presented and demonstrated selectively. Chitosan and alginic acid are structurally similar to glycosaminoglycans (GAGs), which are constituents of human amyloid fibrils. The staining sequences shown can be used as reliable methods for histochemistry with light and polarization microscopy. They will help to clarify the complex protein-polysaccharide structure of amyloid fibrils.

Antimicrobial and anti-inflammatory activity of chitosan-alginate nanoparticles: a targeted therapy for cutaneous pathogens

Advances in nanotechnology have demonstrated potential application of nanoparticles (NPs) for effective and targeted drug delivery. Here we investigated the antimicrobial and immunological properties and the feasibility of using NPs to deliver antimicrobial agents to treat a cutaneous pathogen. NPs synthesized with chitosan and alginate demonstrated a direct antimicrobial activity in vitro against Propionibacterium acnes, the bacterium linked to the pathogenesis of acne. By electron microscopy (EM) imaging, chitosan-alginate NPs were found to induce the disruption of the P. acnes cell membrane, providing a mechanism for the bactericidal effect. The chitosan-alginate NPs also exhibited anti-inflammatory properties as they inhibited P. acnes-induced inflammatory cytokine production in human monocytes and keratinocytes. Furthermore, benzoyl peroxide (BP), a commonly used antiacne drug, was effectively encapsulated in the chitosan-alginate NPs and demonstrated superior antimicrobial activity against P. acnes compared with BP alone while demonstrating less toxicity to eukaryotic cells. Together, these data suggest the potential utility of topical delivery of chitosan-alginate NP-encapsulated drug therapy for the treatment of dermatologic conditions with infectious and inflammatory components.

Factorial design analysis and optimisation of alginate-Ca-chitosan microspheres

The purpose of this study was to apply factorial design in order to determine the influence of the formulation factors and their interactions on several responses such as particle size, dissolution behaviour at pH 1.2 and pH 7.4 as well as production yield, during the development of budesonide loaded, chitosan coated Ca-alginate microparticles (MPs) intended for treatment of inflammatory diseases in the gastrointestinal tract. Produced drug-loaded MPs were spherical in shape, had smooth surfaces with low porosity and size range between 5 and 11 µm. Production yield for the formulations from the design varied from 19% to 50%. Optimisation was performed using central composite design setting the targets: particle size at 5.5 µm, maximised yield, suppressed dissolution at pH 1.2 and sustained release at pH 7.4. The optimised batches were identified with a combined desirability value of 0.967.

Preparation and characterization of chitosan microsphere loading bovine serum albumin

To optimize the preparation process of chitosan microspheres and study its loading capacity, chitosan microsphere was prepared by crosslinking with glutaraldehyde, and bovine serum albumin (BSA) was absorbed onto chitosan microsphere. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FITR), TA instruments and zeta potentiometer analyzer were used to characterize the parameters with respect to size, thermal characters, morphology, and zeta potential of the microspheres. The loading capability and in vitro release tests were carried out. The results showed that chitosan microsphere with particle size less than 10 μm and positively charged (+25.97±0.56 mV) can be obtained under the aldehyde group to amino group ratio at 1:1. A loading capacity of BSA at 28.63±0.15 g/100 g with corresponding loading efficiency at 72.01±1.44% was obtained for chitosan microsphere. In vitro test revealed a burst release followed by sustained-release profile.

Protein micro and nanoencapsulation within glycol-chitosan/Ca²+/alginate matrix by spray drying

Encapsulation of therapeutic peptides and proteins into polymeric micro and nanoparticulates has been proposed as a strategy to overcome limitations to oral protein administration. Particles having diameter less than 5 µm are able to be taken up by the M cells of Peyer's patches found in intestinal mucosa. Current formulation methodologies involve organic solvents and several time consuming steps. In this study, spray drying was investigated to produce protein loaded micro/nanoparticles, as it offers the potential for single step operation, producing dry active-loaded particles within the micro to nano-range. Spherical, smooth surfaced particles were produced from alginate/protein feed solutions. The effect of operational parameters on particle properties such as recovery, residual activity and particle size was studied using subtilisin as model protein. Particle recovery depended on the inlet temperature of the drying air, and mean particle size ranged from 2.2 to 4.5 µm, affected by the feed rate and the alginate concentration in the feed solution. Increase in alginate:protein ratio increased protein stability. Presence of 0.2 g trehalose/g particle increased the residual activity up to 90%. Glycol-chitosan-Ca(2+)alginate particles were produced in a single step operation, with resulting mean diameter of 3.5 μm. Particles showed fluorescein isothiocyanate labeled bovine serum albumin (BSA)-protein entrapment with increasing concentration toward the particle surface. Similar, limited release profiles of BSA, subtilisin and lysozyme were observed in gastric simulation, with ultimate full release of the proteins in gastrointestinal simulation.

Chitosan nanoparticles: a promising system in novel drug delivery

The ability of nanoparticles to manipulate the molecules and their structures has revolutionized the conventional drug delivery system. The chitosan nanoparticles, because of their biodegradability, biocompatibility, better stability, low toxicity, simple and mild preparation methods, offer a valuable tool to novel drug delivery systems in the present scenario. Besides ionotropic gelation method, other methods such as microemulsion method, emulsification solvent diffusion method, polyelectrolyte complex method, emulsification cross-linking method, complex coacervation method and solvent evaporation method are also in use. The chitosan nanoparticles have also been reported to have key applications in parentral drug delivery, per-oral administration of drugs, in non-viral gene delivery, in vaccine delivery, in ocular drug delivery, in electrodeposition, in brain targeting drug delivery, in stability improvement, in mucosal drug delivery in controlled drug delivery of drugs, in tissue engineering and in the effective delivery of insulin. The present review describes origin and properties of chitosan and its nanoparticles along with the different methods of its preparation and the various areas of novel drug delivery where it has got its application.