An in vitro evaluation of a chitosan-containing multiparticulate system for macromolecule delivery to the colon

Chitosan-melanin complex microsphere: A potential colonic delivery system for protein drugs

The characteristics and performance of chitosan-based colon delivery systems are significantly influenced by the method of preparation. Insect chitosan-melanin complex (CMC) may offer superior attributes over traditional shrimp and crab chitosan (CS) for colon-targeted administration. This study used dung beetle CMC as the carrier matrix and comprehensively examined the impact of various crosslinking techniques on the colonic drug delivery efficacy of microspheres, encompassing drug loading, swelling, drug release behavior, adhesion, enzymatic degradation, and absorption enhancement. The results indicate that F-TPPLC microspheres, crosslinked with a combination of formaldehyde and sodium tripolyphosphate, exhibit superior drug loading capabilities, optimal swelling behavior, and controlled in vitro drug release profiles in the colonic environment, along with excellent adhesion and enzymatic degradation properties within intestinal tract. Notably, these F-TPPLC microspheres increase paracellular permeability, possibly by disrupting the calcium-dependent adhesion junctions. In comparison to commercial CS, CMC demonstrates superior drug encapsulation efficiency, enhanced colonic drug release, adhesion, and absorption promotion, rendering it a favorable candidate as a carrier in colon-targeted drug delivery systems. Consequently, F-TPPLC microspheres derived from CMC are highly suitable for colon drug delivery applications and show promising potential for the oral delivery of peptide and protein-based therapeutics to the colon.

Sweeten the pill: Multi-faceted polysaccharide-based carriers for colorectal cancer treatment

Colorectal cancer (CRC) ranks as the second deadliest cancer globally and the third most common malignant tumor. While surgery remains the primary treatment for CRC, alternative therapies such as chemotherapy, molecular targeted therapy, and immunotherapy are also commonly used. The significant side effects and toxicity of conventional drugs drive the search for novel targeted therapies, including the design of advanced drug delivery systems. Polysaccharide-based biopolymers, with their low toxicity, non-immunogenic behavior, synergistic interactions with other biopolymers, and tissue and cell compatibility, emerge as excellent drug carriers for this application. This review aims to provide an in-depth overview of recent advancements in developing polysaccharide-based biopolymeric carriers for anticancer compounds in the treatment of CRC. We highlight the multifunctional nature of polysaccharides, showcasing their potential as standalone drug carriers or as integral components of intelligent robotic devices for biomedical therapeutic applications. In addition to exploring the opportunities for using carbohydrate polymers in CRC treatment, we address the challenges and failures that may limit their applicability in biomedical research, as well as summarize the recent preclinical and clinical trials, resulting in several commercialization attempts. This comprehensive overview critically summarizes the potential of polysaccharide-based biomaterials in CRC treatment.

The Preparation and Characterization of Chitosan/Calcium Phosphate Composite Microspheres for Biomedical Applications

In this study, we successfully prepared porous composite microspheres composed of hydroxyapatite (HAp), di-calcium phosphate di-hydrated (DCPD), and chitosan through the hydrothermal method. The chitosan played a crucial role as a chelating agent to facilitate the growth of related calcium phosphates. The synthesized porous composite microspheres exhibit a specific surface area of 38.16 m2/g and a pore volume of 0.24 cm3/g, with the pore size ranging from 4 to 100 nm. Given the unique properties of chitosan and the exceptional porosity of these composite microspheres, they may serve as carriers for pharmaceuticals. After being annealed, the chitosan transforms into a condensed form and the DCPD transforms into Ca2P2O7 at 300 °C. Then, the Ca2P2O7 initially combines with HAp to transform into β tricalcium phosphate (β-TCP) at 500 °C where the chitosan is also completely combusted. Finally, the microspheres are composed of Ca2P2O7, β-TCP, and HAp, also making them suitable for applications such as injectable bone graft materials.

Quality by Design Approach for Optimization of Microbial and pH-Triggered Colon-Targeted Tablet Formulation Using Carboxymethyl Tamarind Gum

ABSTRACT The purpose of this study was to apply the quality by design (QbD) approach in the development of a microbial and pH-triggered colon-targeted budesonide tablet. A retrospective research strategy was used to select various polysaccharide-based natural gums such as tamarind gum, gellan gum, karaya gum, gum ghutti, and khaya gum, which were then evaluated for their effectiveness in microbial degradation and targeting the colon. Viscosity profiles were generated in the presence of a prebiotic culture medium prepared by using the Velgut capsule that mimicked the impact of 4% rat cecal content and helpful in screening of natural polymer. Based on the cumulative drug release data of preliminary batches, carboxymethyl (CM) tamarind gum was identified as a superior and an excellent polymer over the tamarind gum for formulation development. The presence of water as a bridging agent in wet granulation also played an important role in the retardation of drug release. Tablets were supercoated with the enteric polymer, Eudragit S100. The Box-Behnken design was utilized, where the selected independent variables were the proportion of CM tamarind gum, % water proportion, and % weight gain of Eudragit S 100 to optimize the formulation. The optimized design space was generated with the criteria that a drug release should be of less than 5% within the first 2 h, less than 10% within the first 5 h, and more than 70% within the first 8 h, to achieve colon targeting. The optimized batch F3 was found stable as per International Council for Harmonisation guidelines. The roentgenography study for optimized formulation demonstrated that it remained intact for 5 h and, at 7 h, was disseminated completely. CM tamarind gum is efficient for colon targeting, and its proportion in 100 mg along with an enteric coating of 6% led to the optimized formulation.

Alginate-chitosan-microencapsulated tyrosols/oleuropein-rich olive mill waste extract for lipopolysaccharide-induced skin fibroblast inflammation treatment

The Ca2+ ion-driven emulsification-ionotropic gelation method produced chitosan-alginate microspheres (CAMSs) with a narrow particle size distribution (PSD). Particle size distribution and zeta potential studies, as well as spectral electron microscopy, were used to assess the microspheres' physicochemical properties and morphology. The tyrosols (hydroxytyrosol (HT), tyrosol (TY), and oleuropein (OE) were loaded into these microspheres using a polyphenol extract (PPE) from Koroneki olive mill waste (KOMW). The microencapsulation efficiency and loading capacity of microspheres for PPE were 98.8% and 3.9%, respectively. Three simulated fluids, including gastric (pH = 1.2), intestinal (pH = 6.8), and colonic (pH = 7.4), were used to examine how the pH of the releasing medium affected the ability of CAMSs to release bioactive phenols. At a severely acidic pH (1.2, SGF), PPE release is nearly halted, while at pH 6.8 (SCF), release is at its maximum. Additionally, the PPE-CAMPs have ameliorated the endogenous antioxidant content SOD, GST, GPx with significant values from 0.05 to 0.01 in the treated LPS/human skin fibroblast cells. The anti-inflammatory response was appeared through their attenuations activity for the released cytokines TNF-α, IL6, IL1β, and IL 12 with levels significantly from 0.01 to 0.001. Microencapsulation of PPE by CAMPs significantly improved its antioxidant and anti-inflammatory capabilities.

Metronidazole Delivery Nanosystem Able To Reduce the Pathogenicity of Bacteria in Colorectal Infection

Metronidazole (MTZ) is a drug potentially used for the treatment of intestinal infections, namely, the ones caused by colorectal surgery. The traditional routes of administration decrease its local effectiveness and present off-site effects. To circumvent such limitations, herein a drug delivery system (DDS) based on MTZ-loaded nanoparticles (NPs) immobilized at the surface of electrospun fibrous meshes is proposed. MTZ at different concentrations (1, 2, 5, and 10 mg mL^-1) was loaded into chitosan-sodium tripolyphosphate NPs. The MTZ loaded into NPs at the highest concentration showed a quick release in the first 12 h, followed by a gradual release. This DDS was not toxic to human colonic cells. When tested against different bacterial strains, a significant reduction of Escherichia coli and Staphylococcus aureus was observed, but no effect was found against Enterococcus faecalis. Therefore, this DDS offers high potential to locally prevent the occurrence of infections after colorectal anastomosis.

Response surface method for optimization of prepared satranidazole powder layered pellets

Background

The purpose of the present study was to evaluate layered of satranidazole powder using natural polysaccharides as coating materials for colon targeting that were inexpensive and natural with a non-toxic nature using a composite response design of 3 levels and 2 factors for each of the four responses in the quadratic model. The independent variables were the ratio of coating consistency % (X1) and coating level % (X2) in the pellet. The dependent factors were % release of drug at 2 h. (Y1), % release of drug at 6 h. (Y2), % release of drug difference in presence & absence of colonic enzyme (Y3) and mean dissolution time (Y4). The various models were fitted for the responses with an explanation of suitable statistical methods. Variance analysis and different factor levels of responses were constructed by response surface plots.

Results

Satranidazole pellets were efficiently prepared by the variable amount of ingredients that showed compatibility with possible pellet characterization and drug dissolution profiles to optimize the formulation.

Conclusions

The strategy of response surface can be a successful tool for improving the prepared satranidazole pellets which can be an appropriate replacement of regular one.

Anti-Inflammatory Activity of Chitosan and 5-Amino Salicylic Acid Combinations in Experimental Colitis

Chitosan is used in various drug delivery approaches as a pharmaceutical excipient. Although its potential as an immunomodulatory agent has been reported, its use in this capacity has not been fully explored. The efficacy of chitosan as an active pharmacological agent, particularly in anti-inflammatory therapy in inflammatory bowel diseases (IBD), was investigated in this study. The potential impact of the molecular weight (MW) and degree of deacetylation (DD) of chitosan was investigated together with 5-amino salicylic acid (5-ASA) for its efficacy in a combination anti-inflammatory therapy in murine experimental colitis. Such a combination would potentially be developed into novel dual strategies whereby chitosan acts as a mucoadhesive excipient as well as provide an additional anti-inflammatory benefit. Chitosan grades with different MW and DD were administered intrarectally alone or in combination with 5-ASA to colitis mice for 3 days. Myeloperoxidase (MPO) and alkaline phosphatase (ALP) activity and tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and nuclear factor kappa-B (NF-κB) levels were assessed from the colon. Intrarectal treatment of colitis with 30 mg/kg chitosan alone and with 30 mg/kg 5-ASA for 3 days led to a significant decrease in MPO, ALP, TNF-α, IL-6, IL-1β and NF-κB in colitis mice compared to untreated mice. Surprisingly, the efficacy of chitosan as an anti-inflammatory polymer was relatively independent from its structural properties, namely DD and MW. However, combinations of chitosan with 5-ASA showed a significant pharmacological improvement, whereby the additive anti-inflammatory efficacy observed shows the possibility of finetuning chitosan by combining it with anti-inflammatory agents to optimize its anti-inflammatory potential.

Recent advances in polymeric drug delivery systems

BACKGROUND

Polymeric drug delivery systems have been achieved great development in the last two decades. Polymeric drug delivery has defined as a formulation or a device that enables the introduction of a therapeutic substance into the body. Biodegradable and bio-reducible polymers make the magic possible choice for lot of new drug delivery systems. The future prospects of the research for practical applications has required for the development in the field.

MAIN BODY

Natural polymers such as arginine, chitosan, dextrin, polysaccharides, poly (glycolic acid), poly (lactic acid), and hyaluronic acid have been treated for polymeric drug delivery systems. Synthetic polymers such as poly (2-hydroxyethyl methacrylate), poly(N-isopropyl acrylamide)s, poly(ethylenimine)s, dendritic polymers, biodegradable and bio-absorbable polymers have been also discussed for polymeric drug delivery. Targeting polymeric drug delivery, biomimetic and bio-related polymeric systems, and drug-free macromolecular therapeutics have also treated for polymeric drug delivery. In polymeric gene delivery systems, virial vectors and non-virial vectors for gene delivery have briefly analyzed. The systems of non-virial vectors for gene delivery are polyethylenimine derivatives, polyethylenimine copolymers, and polyethylenimine conjugated bio-reducible polymers, and the systems of virial vectors are DNA conjugates and RNA conjugates for gene delivery.

CONCLUSION

The development of polymeric drug delivery systems that have based on natural and synthetic polymers are rapidly emerging to pharmaceutical fields. The fruitful progresses have made in the application of biocompatible and bio-related copolymers and dendrimers to cancer treatment, including their use as delivery systems for potent anticancer drugs. Combining perspectives from the synthetic and biological fields will provide a new paradigm for the design of polymeric drug and gene delivery systems.

Optimization of Chitosan-Alginate Microparticles for Delivery of Mangostins to the Colon Area Using Box-Behnken Experimental Design

Chitosan-alginate microparticles loaded with hydrophobic mangostins present in the mangosteen rind extract have been formulated and optimized for colon-targeted bioactive drug delivery systems. The chitosan–mangostin microparticles were prepared using the ionotropic gelation method with sodium tripolyphosphate as the cross-linking agent of chitosan. The chitosan–mangostin microparticles were then encapsulated in alginate with calcium chloride as the linking agent. The mangostin release profile was optimized using the Box–Behnken design for response surface methodology with three independent variables: (A) chitosan–mangostin microparticle size, (B) alginate:chitosan mass ratio, and (C) concentration of calcium chloride. The following representative equation was obtained: percent cumulative release of mangostins (10 h) = 59.51 − 5.16A + 20.00B − 1.27C − 1.70AB − 5.43AC − 5.04BC + 0.0579A² + 10.25B² + 1.10C². Cumulative release of 97% was obtained under the following optimum condition for microparticle preparation: chitosan–mangosteen particle size < 100 µm, alginate:chitosan mass ratio of 0.5, and calcium chloride concentration of 4% w/v. The alginate to chitosan mass ratio is the statistically significant variable in the optimization of sequential release profile of mangostins in simulated gastrointestinal fluids. Furthermore, a sufficient amount of alginate is necessary to modify the chitosan microparticles and to achieve a complete release of mangostins. The results of this work indicate that the complete release of mangostins to the colon area can be achieved using the chitosan–alginate microparticles as the bioactive delivery system.

A Comparative Study of Chitosan Gel and Soframycin in the Management of Wounds

Wounds and related injuries remain a major cause of death and disability. Healing of wound is a complex, highly regulated process that includes cellular, molecular, biochemical, and physiological events that permit living organisms to repair accidental lesions. Therefore, dealing with wounds has always been a subject of concern to the world, and demand for products in wound management had increased to $9.3 trillion worldwide in the health care industry, affecting economic growth. The present work aimed to assess the wound healing effect of chitosan, and a comparative profile with soframycin is established in experimental animals. Enormous research reports, the wound healing properties of chitosan, but the protective mechanism implicated in wound healing activity of chitosan is unknown. In addition to this, we evaluated the anatomical, macroscopical, and histopathological alterations in wounds of experimental rats. Collagenase activity was performed to determine the granulation tissue formation and epithelialization of wounds treated with untainted chitosan. Wounds treated with glycerated chitosan gel, that is, GCG-3 (high degree of deacetylation), showed faster healing with highest percentage of contraction as compared with the soframycin-treated group. The healing of wounds was found to be 85% in GCG-3 on the sixth day of treatment, showing significant ( P < .001) improvement in epithelial tissue. The collagenase activity in GCG-3 was 192 unit/mg of protein. Wound reepithelialization was found to be to 94 ± 4% in case of the GCG-3-treated group and 87 ± 5% in the soframycin-treated group. Higher degree of deacetylation in the chitosan, GCG-3, warrants its use in the treatment and management of dermal wounds.

Enhanced oral absorption of insulin using colon-specific nanoparticles co-modified with amphiphilic chitosan derivatives and cell-penetrating peptides

In this study, amphipathic chitosan derivative (ACS) and cell-penetrating peptide (CPP) co-modified colon-specific nanoparticles (CS-CPP NPs) were prepared and evaluated to improve the oral bioavailability of protein and peptide drugs. ACS modification was harnessed to protect CPPs from degradation in the stomach and small intestine after oral administration and achieve colon-specific drug delivery. After CS-CPP NPs reached the colon, ACSs on the surface of the NPs were gradually degraded and CPPs were exposed to bring into play the penetration efficacy in the colon epithelium. Herein, we synthesized four types of ACSs (TOCS, TDCS, TPCS and TSCS) and adopted three types of CPPs (Tat, Penetratin and R8) to prepare NPs (TOCS-Tat NPs, TDCS-Tat NPs, TPCS-Tat NPs, TSCS-Tat NPs, TDCS-Pen NPs and TDCS-R8 NPs). The study of the protective effects of ACS upon Tat showed that the modification of ACS exerted favourable protection upon Tat in the stomach and small intestine. ACS degradation in the colon was indirectly determined in the viscosity method, which indicated that ACS could be gradually degraded in the colon. Using Caco-2 cell monolayers as cell models, it was found that the cellular uptake amount and transcellular transportation performance of CS-CPP NPs were much enhanced compared with those of TDCS NPs and PVA NPs. With Bama mini-pigs as animal models, the pharmacodynamic study demonstrated that the hypoglycemic effect for insulin-loaded TDCS-Tat NPs was more significant than that for TDCS NPs, lowering the blood glucose by 40%. The pharmacokinetic study indicated that the AUC and Cmax for TDCS-Tat NPs were respectively increased by 1.45 times and 1.82 times compared with those of TDCS NPs. In conclusion, CS-CPP NPs as vehicles for colon-specific drug delivery systems may be an efficient approach to improve the oral absorption of protein and peptide drugs.

Preparation, Characterization, and Release Kinetics of Chitosan-Coated Nanoliposomes Encapsulating Curcumin in Simulated Environments

Curcumin, a natural polyphenol, has many biological properties, such as anti-inflammatory, antioxidant, and anti-carcinogenic properties, yet, its sensitivity to light, oxygen, and heat, and its low solubility in water renders its preservation and bioavailability challenging. To increase its bioaccessibility, we fabricated nanoliposomes and chitosan-coated nanoliposomes encapsulating curcumin, and we evaluated the systems in terms of their physicochemical characteristics and release profiles in simulated gastrointestinal mediums. Chitosan-coating enhanced the stability of nanoliposomes and slowed the release of curcumin in the simulated gastrointestinal (GI) environment. This study demonstrates that nanoliposomes and chitosan-coated nanoliposomes are promising carriers for poorly soluble lipophilic compounds with low oral bioavailability, such as curcumin.

Enhanced oral absorption of sorafenib via the layer-by-layer deposition of a pH-sensitive polymer and glycol chitosan on the liposome

This study aimed to design the effective formulation of sorafenib (SF) to enhance the oral drug absorption. Three liposomal formulations of SF were prepared including uncoated liposome (SF-Lip), glycol chitosan-coated liposome (GC-SF-Lip), and Eudragit S100-glycol-chitosan coated liposome (SGC-SF-Lip). All formulations showed a narrow size distribution with a high encapsulation efficiency. Both GC-SF-Lip and SGC-SF-Lip exhibited good stability at acidic and neutral pHs without any significant drug leakage, while SF-Lip appeared to be unstable at pH 1.2. In the case of double coated SGC-SF-Lip, its size changed significantly at pH 7.4, due to the dissolution of Eudragit S100 coating layer into the surrounding medium. Compared to SF solution, all liposomal formulations demonstrated a higher cellular uptake in Caco-2 cells. In particular, SGC-SF-Lip displayed a lower cellular uptake than GC-SF-Lip at pH 6.5, but it achieved a similar cellular uptake to GC-SF-Lip at pH 7.4. Consistently, SGC-SF-Lip was less cytotoxic than GC-SF-Lip at pH 6.5, whereas it showed a comparable cytotoxicity to GC-SF-Lip at pH 7.4, implying the removal of the Eudragit S100 coating layer at pH 7.4. After an oral administration to rats, SGC-SF-Lip significantly improved the systemic exposure of SF, where its Cmax and AUC were approximately fourfold higher than the untreated drug. Collectively, SGC-SF-Lip appeared to be promising to enhance the oral absorption of SF.

Development of a chitosan based double layer-coated tablet as a platform for colon-specific drug delivery

A double layer-coated colon-specific drug delivery system (DL-CDDS) was developed, which consisted of chitosan (CTN) based polymeric subcoating of the core tablet containing citric acid for microclimate acidification, followed by an enteric coating. The polymeric composition ratio of Eudragit E100 and ethyl cellulose and amount of subcoating were optimized using a two-level factorial design method. Drug-release characteristics in terms of dissolution efficiency and controlled-release duration were evaluated in various dissolution media, such as simulated colonic fluid in the presence or absence of CTNase. Microflora activation and a stepwise mechanism for drug release were postulated. Consequently, the optimized DL-CDDS showed drug release in a controlled manner by inhibiting drug release in the stomach and intestine, but releasing the drug gradually in the colon (approximately 40% at 10 hours and 92% at 24 hours in CTNase-supplemented simulated colonic fluid), indicating its feasibility as a novel platform for CDD.

Design and preparation of a novel colon-targeted tablet of hydrocortisone

ABSTRACT The objective of this research was to design a new colon-targeted drug delivery system based on chitosan. The properties of the films were studied to obtain useful information about the possible applications of composite films. The composite films were used in a bilayer system to investigate their feasibility as coating materials. Tensile strength, swelling degree, solubility, biodegradation degree, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Scanning electron microscope (SEM) investigations showed that the composite film was formed when chitosan and gelatin were jointly reacted jointly. The results showed that a 6:4 blend ratio was the optimal chitosan/gelatin blend ratio. In vitro drug release results indicated that the Eudragit- and chitosan/gelatin-bilayer coating system prevented drug release in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). However, the drug release from a bilayer-coated tablet in SCF increased over time, and the drug was almost completely released after 24 h. Overall, colon-targeted drug delivery was achieved by using a chitosan/gelatin complex film and a multilayer coating system.

Chitosan nanoparticles reduce LPS-induced inflammatory reaction via inhibition of NF-κB pathway in Caco-2 cells

Chitosan nanoparticles (CNP), an extensively oral-administered drug carrier, was investigated for the anti-inflammatory effects on LPS-inflamed Caco-2 cells and the relate mechanisms. CNP could alleviate the decrease of transepithelial electrical resistance (TEER) induced by LPS in Caco-2 monolayer, and significantly inhibit LPS-induced production of TNF-α, MIF, IL-8 and MCP-1 in a dose-dependent manner. PCR array assay revealed that CNP down-regulated the mRNA expression levels of TLR4 in LPS-inflamed Caco-2 cells. CNP was further showed to reduce cytoplasmic IκB-α degradation and nuclear NF-κB p65 levels in LPS-inflamed Caco-2 cells. These results suggested that CNP suppressed LPS-induced inflammatory response by decreasing permeability of intestinal epithelial monolayer and secretion of pro-inflammatory cytokine in Caco-2 cells, which were partially mediated by NF-κB signaling pathway.

Design of chitosan and its water soluble derivatives-based drug carriers with polyelectrolyte complexes

Chitosan, the cationic polysaccharide derived from the natural polysaccharide chitin, has been studied as a biomaterial for more than two decades. As a polycationic polymer with favorable properties, it has been widely used to form polyelectrolyte complexes with polyanions for various applications in drug delivery fields. In recent years, a growing number of studies have been focused on the preparation of polyelectrolyte complexes based on chitosan and its water soluble derivatives. They have been considered well-suited as biomaterials for a number of vital drug carriers with targeted/controlled release profiles, e.g., films, capsules, microcapsules. In this work, an overview highlights not only the favorable properties of chitosan and its water soluble derivatives but also the good performance of the polyelectrolyte complexes produced based on chitosan. Their various types of applications as drug carriers are reviewed in detail.

Formulation of extended release cefpodoxime proxetil chitosan-alginate beads using quality by design approach

The purpose of this work was to develop and characterize chitosan-alginate beads for the extended delivery of cefpodoxime proxetil (CFP), to understand the impact of formulation and process parameters on the critical quality attributes (CQAs) using a quality-by-design approach. For this, a study was performed with various formulation and process parameters to determine their impact on CQAs of beads, which were determined to be time for 80% of the drug released (T80%), particle size, and encapsulation efficiency. The beads of CFP were optimized using a three-factor, three-level Box-Behnken design. A formulation comprising of 4.38% (w/v) alginate, 1.39% (w/v) chitosan and 6.82% (w/v) calcium chloride was found to fulfill requisites of an optimum formulation. In vitro release studies showed that the drug is released from the optimized formulation over a period of 24h in a sustained release manner, primarily by non-Fickian diffusion. The optimized formulation was characterized by DSC, FTIR, XRD and SEM analysis. Antimicrobial studies revealed that the release of the drug over 24h periods was above the minimum concentration required for inhibition of microbial growth. This research highlights the level of understanding that can be accomplished through a well designed study based on the approach of QbD.

Enhanced chitosan beads-supported Fe(0)-nanoparticles for removal of heavy metals from electroplating wastewater in permeable reactive barriers

The removal of heavy metals from electroplating wastewater is a matter of paramount importance due to their high toxicity causing major environmental pollution problems. Nanoscale zero-valent iron (NZVI) became more effective to remove heavy metals from electroplating wastewater when enhanced chitosan (CS) beads were introduced as a support material in permeable reactive barriers (PRBs). The removal rate of Cr (VI) decreased with an increase of pH and initial Cr (VI) concentration. However, the removal rates of Cu (II), Cd (II) and Pb (II) increased with an increase of pH while decreased with an increase of their initial concentrations. The initial concentrations of heavy metals showed an effect on their removal sequence. Scanning electron microscope images showed that CS-NZVI beads enhanced by ethylene glycol diglycidyl ether (EGDE) had a loose and porous surface with a nucleus-shell structure. The pore size of the nucleus ranged from 19.2 to 138.6 μm with an average aperture size of around 58.6 μm. The shell showed a tube structure and electroplating wastewaters may reach NZVI through these tubes. X-ray photoelectron spectroscope (XPS) demonstrated that the reduction of Cr (VI) to Cr (III) was complete in less than 2 h. Cu (II) and Pb (II) were removed via predominant reduction and auxiliary adsorption. However, main adsorption and auxiliary reduction worked for the removal of Cd (II). The removal rate of total Cr, Cu (II), Cd (II) and Pb (II) from actual electroplating wastewater was 89.4%, 98.9%, 94.9% and 99.4%, respectively. The findings revealed that EGDE-CS-NZVI-beads PRBs had the capacity to remediate actual electroplating wastewater and may become an effective and promising technology for in situ remediation of heavy metals.

Characterization of novel lactoferrin loaded capsules prepared with polyelectrolyte complexes

Novel capsules loaded with lactoferrin (LF) were prepared using polyelectrolyte complexes that were formed by water soluble chitosan (WSC), sodium cellulose sulfate (NaCS) and sodium polyphosphate (PPS). Normal chitosan (soluble in acidic conditions) was chosen as a control to prepare similar capsules with NaCS and PPS. (1)H NMR and FTIR spectra analysis showed that WSC was in a form of chitosan hydrochloride which can be directly dissolved and protonated in acid-free water. SEM results showed that the capsules had a typical wall-capsule structure with a regular spherical shape and an average diameter of 1.97 mm. TGA studies revealed that the thermal stability of the capsules were enhanced and the moisture content of the drug-free/loaded capsules were 6.3% and 3.2%. SDS-PAGE results showed that the primary structures of the processed LF in the capsules were unchanged. Drug loading (LE%) and encapsulation efficiency (EE%) analysis showed that the capsules had a higher LE% (45.6%) and EE% (70.7%) than that of the control. In vitro release studies showed that the capsules had a regular and sustainable release profiles in simulated colonic fluid. All of these results indicated that the capsules prepared could be used as a candidate protein drug carrier for colon.

Arabinoxylan microspheres: structural and textural characteristics

The aim of this research was to study the structural and textural characteristics of maize bran arabinoxylan (MBAX) microspheres. The laccase-induced cross-linking process was monitored by storage (G') and loss (G'') moduli changes in a 4% (w/v) MBAX solution. The G' and G'' values at the plateau region were 215 and 4 Pa, respectively. After gelation, the content of ferulic acid dimers decreased from 0.135 to 0.03 µg/mg MBAX, suggesting the formation of ferulated structures unreleased by mild alkaline hydrolysis. MBAX microspheres presented an average diameter of 531 µm and a swelling ratio value (q) of 18 g water/g MBAX. The structural parameters of MBAX microspheres were calculated from equilibrium swelling experiments, presenting an average mesh size of 52 nm. Microstructure and textural properties of dried MBAX microspheres were studied by scanning electron microscopy and nitrogen adsorption/desorption isotherms, respectively, showing a heterogeneous mesoporous and macroporous structure throughout the network.

Approaches for enhancing oral bioavailability of peptides and proteins

Oral delivery of peptide and protein drugs faces immense challenge partially due to the gastrointestinal (GI) environment. In spite of considerable efforts by industrial and academic laboratories, no major breakthrough in the effective oral delivery of polypeptides and proteins has been accomplished. Upon oral administration, gastrointestinal epithelium acts as a physical and biochemical barrier for absorption of proteins resulting in low bioavailability (typically less than 1-2%). An ideal oral drug delivery system should be capable of (a) maintaining the integrity of protein molecules until it reaches the site of absorption, (b) releasing the drug at the target absorption site, where the delivery system appends to that site by virtue of specific interaction, and (c) retaining inside the gastrointestinal tract irrespective of its transitory constraints. Various technologies have been explored to overcome the problems associated with the oral delivery of macromolecules such as insulin, gonadotropin-releasing hormones, calcitonin, human growth factor, vaccines, enkephalins, and interferons, all of which met with limited success. This review article intends to summarize the physiological barriers to oral delivery of peptides and proteins and novel pharmaceutical approaches to circumvent these barriers and enhance oral bioavailability of these macromolecules.

In vitro evaluation of paclitaxel loaded amorphous chitin nanoparticles for colon cancer drug delivery

Chitin and its derivatives have been widely used in drug delivery applications due to its biocompatible, biodegradable and non-toxic nature. In this study, we have developed amorphous chitin nanoparticles (150±50 nm) and evaluated its potential as a drug delivery system. Paclitaxel (PTX), a major chemotherapeutic agent was loaded into amorphous chitin nanoparticles (AC NPs) through ionic cross-linking reaction using TPP. The prepared PTX loaded AC NPs had an average diameter of 200±50 nm. Physico-chemical characterization of the prepared nanoparticles was carried out. These nanoparticles were proven to be hemocompatible and in vitro drug release studies showed a sustained release of PTX. Cellular internalization of the NPs was confirmed by fluorescent microscopy as well as by flow cytometry. Anticancer activity studies proved the toxicity of PTX-AC NPs toward colon cancer cells. These preliminary results indicate the potential of PTX-AC NPs in colon cancer drug delivery.

Development of pH- and enzyme-controlled, colon-targeted, pulsed delivery system of a poorly water-soluble drug: preparation and in vitro evaluation

BACKGROUND

As conventional pH-controlled colon-targeted system used for oral drug delivery often shows a poor performance, a more effective way to preserve poorly water-soluble drug from releasing in upper gastrointestinal tract should be researched.

METHOD

The objective of this study was to develop a novel colon-targeted drug delivery system using guar gum and Eudragit as enzyme- and pH-based materials. Lansoprazole, a poorly water-soluble drug was used as model drug. Under three different conditions, the in vitro drug release behaviors of this newly developed system was evaluated, using β-mannanase, rat cecal content, and human fecal media to simulate the pH and enzyme during intestinal transit to the colon.

RESULTS

The released amount of lansoprazole in simulated small intestine fluid (pH 6.8) after 5 hours was less than 10% from the pH- and enzyme-controlled tablets compared with 80.01±0.3% in rat cecal content medium (pH 7.4).The degradation ability of human fecal slurries on PECCT-PT was independent of human age and gender. β-Mannanase did not have a similar effect on the degradation of polysaccharide as rat cecal enzymes and human fecal enzymes in our study. Scanning electron microscope study indicated that the dissolution mechanism of PECCT-PT should be corrosion.

CONCLUSION

The above results indicated this system could be served as a potential carrier to deliver poorly water-soluble drug specifically to the colon.

Enhanced delivery of baicalein using cinnamaldehyde cross-linked chitosan nanoparticle inducing apoptosis

The chitosan (CS) nanoparticles, baicalein loaded chitosan nanoparticles were prepared by crosslinking method in a W/O emulsion system, using cinnamaldehyde as crosslinking agent. The FT-IR result showed the binding of anticancer compound baicalein to the nanoparticles. The TEM analysis revealed that the particles are spherical in nature. Zeta potential revealed negative charge of the particles. Ultraviolet spectrum analysis described that higher loading efficiency and encapsulation efficiency as 9.1% and 97.2%, respectively. In vitro baicalein release profile demonstrated the delivery of baicalein from the CS nanoparticles is a two stage process. RT-PCR and cell culture was carried out accordingly.

Chitosan-tripolyphosphate submicron particles as the carrier of entrapped rutin

Chitosan (CH)-tripolyphosphate (TPP) submicron particles were formed as carriers of entrapped rutin, and the release properties characterized using simulated gastric juices and fluids of the small intestine. Particle size, charge and entrapment efficiencies were investigated as a function of the CH:TPP molar ratio (2.0:1.0-5.0:1.0). Size was found to decrease from ~814 nm for the 2.0:1:0 mass ratio to ~528 nm for the ratios between 2.5:1.0 and 4.0:1.0, and then again to ~322 nm for the 5:0:1.0 mass ratio, whereas all particles carried a positive surface charge, increasing from +21 to +59 mV as the ratio increased from 2.0:1.0 to 5.0:1.0. The percent entrapment was found to rise from 3.68% to 57.6% as the ratios increased from 2.0:1:0 to 4.0:1:0, before reaching a plateau. Submicron particles (4.0:1.0 mass ratio only) were found to retain rutin in simulated gastric fluids, whereas in conditions which simulated fluids from the small intestine, only 20% of the entrapped rutin was released and 80% remained absorbed to the CH:TPP carriers. Such particles have applications for the delivery of phenolics in food and natural health products.

Polymers for colon targeted drug delivery

The colon targeted drug delivery has a number of important implications in the field of pharmacotherapy. Oral colon targeted drug delivery systems have recently gained importance for delivering a variety of therapeutic agents for both local and systemic administration. Targeting of drugs to the colon via oral administration protect the drug from degradation or release in the stomach and small intestine. It also ensures abrupt or controlled release of the drug in the proximal colon. Various drug delivery systems have been designed that deliver the drug quantitatively to the colon and then trigger the release of drug. This review will cover different types of polymers which can be used in formulation of colon targeted drug delivery systems.