Influence of glutaraldehyde on drug release and mucoadhesive properties of chitosan microspheres

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.

Bacterial cellulose nanocrystal as drug delivery system for overcoming the biological barrier of cyano-phycocyanin: a biomedical application of microbial product

Phycocyanin, produced by Spirulina platensis, has been reported as an anti-inflammatory, anti-hyperalgesia, antioxidant, anti-tumor, and anti-cancer agent. However, the ingestion of phycocyanin in the body is often hindered by its instability against gastric pH conditions. The nano-drug delivery system has developed as a promising platform for efficient drug delivery and improvement as well as drug efficacy. Bacterial cellulose nanocrystal (BCNC) has it superiority as DDS due to its inherent properties such as nanoscale dimension, large surface area, - biocompatibility, and non-toxic. To improve its mechanical properties, BCNC was crosslinked with glutaraldehyde and was analyzed as a potential candidate for DDS. The Fourier transform infrared analysis of the BCNC suggested that hydrolysis did not alter the chemical composition. The index of crystallinity of the BCNC was 18.31% higher than that of the original BC, suggesting that crystalline BC has been successfully isolated. The BCNC particle also showed a needle-like morphology which is 25 ± 10 nm in diameter and a mean length of 626 ± 172 nm. Crosslinked BCNC also had larger pores than the original BCNC along with higher thermal stability. Optimum phycocyanin adsorption on crosslinked BCNC reached 65.3% in 3 h. The release study shows that the crosslinked BCNC can protect the phycocyanin retardation by gastric fluid until phycocyanin reaches the targeted sites. This study provides an alternative potential DDS derived from natural bioresources with less expenses and better properties to promote the application of BCNC as functional nanomaterials in biomedical science.

Modulating the Effect of β-Sitosterol Conjugated with Magnetic Nanocarriers to Inhibit EGFR and Met Receptor Cross Talk

The cross-talk between the EGFR (Epidermal Growth Factor Receptor) and MET (Hepatocyte Growth Factor Receptor) poses a significant challenge in the field of molecular signaling. Their intricate interplay leads to dysregulation and contributes to cancer progression and therapeutic resistance. β-Sitosterol (BS), a plant sterol with promising anticancer properties, shows increased research on its potential as a chemopreventive agent. However, significant modifications are required to deliver BS in cancer cells due to its lower efficacy. The present work aims to design a carrier-mediated delivery system specifically targeting cancer cells with EGFR and MET receptor cross-talk. Surface modification of BS was performed with superparamagnetic iron oxide nanoparticles (SPIONs), polyethylene glycol (PEG), and poly(N-isopropylacrylamide) (PNIPAM) to enhance the delivery of BS at the target site. BS was conjugated with SPIONs (BS-S), PNIPAM (BS-SP), PEG, and PNIPAM (BS-SPP) polymers, respectively, and the conjugated complexes were characterized. Results showed an increase in size, stability, and monodispersity in the following order, BS-S, BS-SP, and BS-SPP. The drug encapsulation efficiency was observed to be highest in BS-SPP (82.5%), compared to BS-S (61%) and BS-SP (74.9%). Sustained drug release was achieved in both BS-SP (82.6%) and BS-SPP (83%). The IC 50 value of BS, BS-S, BS-SP, and BS-SPP towards MCF 7 was 242 µg/mL,197 µg/mL, 168 µg/mL, and 149 µg/mL, HEPG2 was 274 µg/mL, 261 µg/mL, 233 µg/mL and 207 µg/mL and NCIH 460 was 191 µg/mL, 185 µg/mL, 175 and 164 µg/mL, indicating highest inhibition towards NCIH 460 cells. Our results conclude that β-sitosterol conjugated with SPION, PEG, and PNIPAM could be a potential targeted therapy in inhibiting EGFR and MET receptor-expressing cancer cells.

Formulation, characterization and cellular toxicity assessment of a novel bee-venom microsphere in prostate cancer treatment

Bee venom (B.V.) is a toxin produced naturally by honey bees with several toxic and therapeutic efficacies. It is used in the treatment of different cancer kinds like renal, hepatic, and prostate cancer. Due to its protein nature, it is degraded in the upper gastrointestinal tract. Colon-targeted drug delivery systems represent a useful tool to protect B.V. from degradation and can be administered orally instead of I.V. infusion and traditional bee stinging. In the present study, B.V. loaded enteric-coated cross-linked microspheres were prepared by emulsion cross-linking method. Percentage yield, entrapment efficiency %, swelling degree, and in-vitro release are evaluated for prepared microspheres. Free B.V., optimized microspheres formula (F3), and doxorubicin cytotoxic effects were tested by MTT assay. Results concluded that free B.V. was more effective against the growth of human prostate adenocarcinoma (PC3) cells followed by optimized microspheres than doxorubicin. But both free B.V. and doxorubicin have a cytotoxic effect on normal oral epithelial cells (OEC). According to flow cytometric analysis, the optimized microsphere formula induced apoptosis and reduced necrosis percent at IC₅₀ concentration. Furthermore, microspheres did not affect the viability of OEC. These results revealed that microspheres have a degree of specificity for malignant cells. Therefore, it seems that this targeted formulation could be a good candidate for future clinical trials for cancer therapy.

In Vitro and In Vivo Evaluations of Berberine-Loaded Microparticles Filled In-House 3D Printed Hollow Capsular Device for Improved Oral Bioavailability

The low oral bioavailability, short biological half-life, high dose, and frequent dosing of berberine (BBR) contribute to its restricted clinical use despite its extensive pharmacological activity. Thus, the objective of this study was to formulate sustained-release microparticles (MPs) using a pH-independent release polymer and to evaluate their potential to improve the oral bioavailability of BBR. BBR loaded MPs were prepared using the emulsion crosslinking method and evaluated for particle size, circularity, morphology, entrapment efficiency, solid-state analysis, swelling index, and in vitro BBR release study fitted with different models of release kinetics. The MPs exhibited desired particle sizes ranges between 11.09-11.62 μm and were almost spherical in shape, as confirmed by the circularity value and micrographic images. A loss of BBR crystallinity was observed after encapsulation in MPs, as evident from various solid-state analyses. The final optimized batch (F3) showed highest % BBR entrapment efficiency value of 81.63% ± 4.9. The in vitro BBR release performance in both acidic and alkaline media showed the desired sustained release behavior from the crosslinked MPs, where the maximum BBR release was observed at alkaline pH, which is in accordance with the swelling study data. In the in vivo study, the oral absorption profiles of BBR from both pristine and MPs formats were investigated using in-house prototyped 3D printed hollow capsules as a unit dose carrier. In vivo data showed sustained and prolonged absorption behavior of BBR from MPs compared to their pristine counterparts, which resulted in a cumulative increment of relative oral bioavailability to mitigate the aforementioned issues related to BBR. Graphical Abstract.

Poloxamer based Urapidil Loaded Chitosan Microparticle in Approach to Improve the Mechanical Strength by Tensile Strength and Entrapment Determination

Background:

The literature review highlighted the issues related to the poor mechanical strength of chitosan-based microparticles. In an attempt to resolve the stated drawback, the microparticles are prepared with a suitable combination of poloxamer-188 (pluronic) and chitosan-based hydrogels.

Objective:

The current study deals with urapidil-loaded chitosan microparticles incorporating chitosan-based hydrogels and small polyanionic electrolytes. The mechanical strength was ascertained by entrapment efficiency and texture analyzer.

Method:

Chitosan-based hydrogels and the combination of poloxamer and further microparticles are prepared by counter-ion aggregation technique in polyanionic electrolyte medium (20 % w/v). During the preparation, poloxamer is incorporated to improve the mechanical strength, which is ascertained in terms of adhesive strength (tensile strength) by texture analyzer and entrapment efficiency. The prepared microparticles are also subjected to micrometric studies, swelling index, surface morphology study, drug-polymer interaction study, and zeta analysis.

Result:

It was observed that there is a remarkable increase in entrapment efficiency (maximum of 78.56 % from SSP4) with the progressive increase in poloxamer-188. In addition to that, adhesive strength was also studied by a texture analyzer for all microparticles. Sodium citrate-based products exhibited superior adhesive strength values compared to sodium sulfate and sodium tripolyphosphate-based and signified the incorporation of poloxamer-188. A significant finding was also recorded for the swelling properties to microenvironmental pH attributed to polyanions. It observed Sodium TPP microparticles continued to swell in phosphate buffer pH 6.8. Zeta value was found to be maximum with -5.2 mV; it could further be improved by adding electrolytes. TPP4 showed a comparatively larger particle size of 8.07 µm. Polydispersity index value ascertained homogenous dispersion of microparticles. SEM study revealed prominent porous surfaces for sodium tripolyphosphate microparticles.

Conclusion:

The study revealed that the addition of poloxamer-188 improved the mechanical strength, identified by entrapment efficiency and texture analysis. SCP4 microparticle was found to be the best formulation among all.

Micro/nanotechnology-inspired rapid diagnosis of respiratory infectious diseases

Humans have suffered from a variety of infectious diseases since a long time ago, and now a new infectious disease called COVID-19 is prevalent worldwide. The ongoing COVID-19 pandemic has led to research of the effective methods of diagnosing respiratory infectious diseases, which are important to reduce infection rate and help the spread of diseases be controlled. The onset of COVID-19 has led to the further development of existing diagnostic methods such as polymerase chain reaction, reverse transcription polymerase chain reaction, and loop-mediated isothermal amplification. Furthermore, this has contributed to the further development of micro/nanotechnology-based diagnostic methods, which have advantages of high-throughput testing, effectiveness in terms of cost and space, and portability compared to conventional diagnosis methods. Micro/nanotechnology-based diagnostic methods can be largely classified into (1) nanomaterials-based, (2) micromaterials-based, and (3) micro/nanodevice-based. This review paper describes how micro/nanotechnologies have been exploited to diagnose respiratory infectious diseases in each section. The research and development of micro/nanotechnology-based diagnostics should be further explored and advanced as new infectious diseases continue to emerge. Only a handful of micro/nanotechnology-based diagnostic methods has been commercialized so far and there still are opportunities to explore.

Antibacterial performance of fully biobased chitosan-grafted-polybenzoxazine films: Elaboration and properties of released material

A fully biobased benzoxazine monomer, V-fa (using vanillin and furfurylamine) was grafted onto chitosan (CS) at different weight ratios (C_XV_Y) using "grafting to" benign Schiff base chemistry. Incorporation of V-fa onto CS increased the tensile strength and improved chemical resistance of the CS-graft-V-fa films. Reversible labile linkages, expansion of CS galleries and leaching out of phenolic species from biobased polymer films led to an improved antibacterial activity against Staphylococcus aureus, which is ∼125 times higher than the bare CS film, V-fa and oligomeric V-fa. The leached out species from films were analyzed extensively by NMR, FTIR, GPC, ABTS and HRMS analysis. Oxidative-stress seems to be responsible for antibacterial activity. Current work illustrates an attractive synthetic approach and the improved antibacterial performance of biobased CS-graft-poly(V-fa) films which may hold as a potential alternative for wound-healing and implant applications in future.

Co-regulative effects of chitosan-fennel seed extract system on the hormonal and biochemical factors involved in the polycystic ovarian syndrome

There is a renewed interest in the application of chitosan-based drug delivery systems over the last few years. In this study, the ionic gelation method was used to prepare chitosan-engaged tripolyphosphate ions, as the cross-linking molecule, (Chit-TPP) and concurrent loading of the biomolecules of the ethanolic extract of fennel, Foeniculum vulgare, seed (FEC@NBC). The samples were characterized by SEM, DLS, TGA, FTIR, XRD, GC-MS, and zeta potential, and their effects on the related hormonal and biochemical factors of the rats with polycystic ovarian syndrome (PCOS) were assessed. The estradiol valerate-induced PCOS in female rats was confirmed by vaginal smear test and subsequent histological screening. The PCOS-induced rats were treated by fennel seed extract (FSX), Chit-TPP, and FEC@NBC. The process of treatment was monitored by measuring the serum levels of testosterone, luteinizing hormone, follicle-stimulating hormone, insulin, glucose, high-density lipoprotein cholesterol, total cholesterol, and total triglyceride after 16 days of treatment and compared with healthy control and untreated PCOS-control groups. The FEC@NBC administration contributed to the remarkable hormonal, glucose, and lipid profile regulation in the rats with PCOS. The significance of FEC@NBC performance in dealing with PCOS complications compared to that of the only extract could be resulted from the effective targeted delivery and stability of phytomolecules when encapsulated in Chit-TPP.

Improved shellac mediated nanoscale application drug release effect in a gastric-site drug delivery system

Six kinds of nanoscale application are designed in this study. A significant increase of drug release rate can be observed at the gastric site.

Effect of mesenchymal stem cells and galantamine nanoparticles in rat model of Alzheimer's disease

AIM

The present study investigated the efficacy of bone marrow-derived mesenchymal stem cells (BM-MSCs) in combination with galantamine hydrobromide-loaded solid lipid nanoparticles (GH-SLNs) in intracerebroventricular (ICV)-isoproterenol-induced rat model of Alzheimer's disease.

MATERIALS & METHODS

BM-MSCs were harvested by dissecting femur and tibia of 8-10-week-old Wistar rats. 1 × 10(6) cells were administered intravenously once in ICV-isoproterenol-induced rats followed by GH-SLNs (5 mg/kg) for 3 weeks.

RESULTS & CONCLUSION

ICV-isoproterenol resulted in significant memory deficit. The results demonstrated rapid regain of memory in isoproterenol-induced amnesic rats, following single intravenous administration of BM-MSCs and oral administration of GH-SLNs for 21 days. The combination of BM-MSCs and GH-SLNs produced a more pronounced protective effect, therefore, could be explored for the management of Alzheimer's disease.

Perspectives on: Chitosan Drug Delivery Systems Based on their Geometries

Chitosan is a natural polymer that has many physicochemical (polycationic, reactive OH and NH2 groups) and biological (bioactive, biocompatible, biodegradable) properties. These unique properties make chitosan an excellent material for the development of new biomedical applications. One of the most well known biomedical chitosan applications is in drug delivery systems. Chitosans have been used in the design of many different types of drug carriers for various administration routes such as oral, bucal, nasal, transdermal, parenteral, vaginal, cervical, intrauterine and rectal. Chitosan can be engineered into different shapes and geometries such as nanoparticles, microspheres, membranes, sponges and rods. This paper is a perspective on the preparation of the chitosan drug delivery systems based on different structural geometries. In this respect, special preparation techniques are used to prepare chitosan drug carriers by altering such parameters as crosslinker concentration, chitosan molecular weight, drug/polymer ratio and processing conditions all of which affect the morphology of chitosan drug carriers and release rate of the loaded drug.

Designing a biocompatible hydrogel for the delivery of mesalamine

A new design for nanocomposite hydrogels based on cross-linked chitosan for the delivery of mesalamine is presented. To enhance drug loading in chitosan, the mineral montmorillonite was incorporated into the matrix. The exfoliated silica montmorillonite nanosheets form interactions with both chitosan and mesalamine, which affect the hydrogel's drug release mechanism and swelling properties. The impact of montmorillonite and glutaraldehyde concentrations on the hydrogel properties was investigated. In vitro drug-release studies detected slower release over short times when montmorillonite was introduced into the matrix. This study is the first to evaluate the influence of pH during mixing and on mixing duration. It was shown that lowering the pH during mixing delayed the release since the positively charged drug was better introduced between the montmorillonite layers, as confirmed by differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FTIR) analysis. All hydrogels showed prolonged sustained release of mesalamine over 24h in simulated colonic fluid (pH 7.4). When modeled, the mesalamine release profile suggests a complex release mechanism, involving adsorption of the drug to the montmorillonite and its diffusion. The results imply that chitosan-montmorillonite hydrogels can serve as potential drug carriers for controlled-release applications.

Didanosine-loaded chitosan microspheres optimized by surface-response methodology: a modified "Maximum Likelihood Classification" approach formulation for reverse transcriptase inhibitors

Didanosine-loaded chitosan microspheres were developed applying a surface-response methodology and using a modified Maximum Likelihood Classification. The operational conditions were optimized with the aim of maintaining the active form of didanosine (ddI), which is sensitive to acid pH, and to develop a modified and mucoadhesive formulation. The loading of the drug within the chitosan microspheres was carried out by ionotropic gelation technique with sodium tripolyphosphate (TPP) as cross-linking agent and magnesium hydroxide (Mg(OH)₂) to assure the stability of ddI. The optimization conditions were set using a surface-response methodology and applying the "Maximum Likelihood Classification", where the initial chitosan concentration, TPP and ddI concentration were set as the independent variables. The maximum ddI-loaded in microspheres (i.e. 1433 mg of ddI/g chitosan), was obtained with 2% (w/v) chitosan and 10% TPP. The microspheres depicted an average diameter of 11.42 μm and ddI was gradually released during 2 h in simulated enteric fluid.

Soya nuggets – a potential carrier: swelling kinetics and release of hydrophobic drugs

Soya nuggets were used as a drug delivery vehicle. The swelling degree of the soya nuggets was responsible for efficient drug loading and release.

Preparation and characterization of the linked lanthanum carboxymethylcellulose microsphere adsorbent for removal of fluoride from aqueous solutions

Linked carboxymethyl cellulose microspheres loaded with lanthanum(iii) (linked-CMC–La) were fabricated with glutaraldehyde. The linked-CMC–La had good adsorption properties compared with CMC–La, and also showed better physical properties.

Poly(acrylic acid)–chitosan–silica hydrogels carrying platelet gels for bone defect repair

A polymer scaffold with an interpenetrating network (IPN) structure between PAA and chitosan with nano-silica as the filler for bone tissue engineering was prepared.

Chemical cross-linking abrogates adjuvant potential of natural polymers

Natural polymers like chitosan and alginic acid are extensively used in biomedicine for different applications.

Polysaccharide drug delivery systems based on pectin and chitosan

Chitosans and pectins are natural polysaccharides which show great potential in drug delivery systems. Chitosans are a family of strongly polycationic derivatives of poly-N-acetyl-D-glucosamine. This positive charge is very important in chitosan drug delivery systems as it plays a very important role in mucoadhesion (adhesion to the mucosal surface). Other chitosan based drug delivery systems involve complexation with ligands to form chitosan nanoparticles with can be used to encapsulate active compounds. Pectins are made of several structural elements the most important of which are the homogalacturonan (HG) and type I rhamnogalacturonan (RG-I) regions often described in simplified terms as the "smooth" and "hairy" regions respectively. Pectin HG regions consist of poly-glacturonic acid residues which can be partially methyl esterified. Pectins with a degree of methyl esterification (DM) > 50% are known as high methoxyl (HM) pectins and consequently low methoxyl (LM) pectins have a DM less than 50%. Low methoxyl pectins are of particular interest in drug delivery as they can form gels with calcium ion (Ca2+) which has potential applications especially in nasal formulations. In this chapter we will discuss the physicochemical properties of both chitosans and pectins and how these translate to current and potential drug delivery systems.