Preparation and characterization of inulin ester microspheres as drug carriers

Inulin-based formulations as an emerging therapeutic strategy for cancer: A comprehensive review

Cancer stands as the second leading cause of death in the United States (US). Most chemotherapeutic agents exhibit severe adverse effects that are attributed to exposure of drugs to off-target tissues, posing a significant challenge in cancer therapy management. In recent years, inulin, a naturally occurring prebiotic fiber has gained substantial attention for its potential in cancer treatment owing to its multitudinous health values. Its distinctive structure, stability, and nutritional properties position it as an effective adjuvant and carrier for drug delivery in cancer therapy. To address some of the above unmet clinical issues, this review summarizes the recent efforts towards the development of inulin-based nanomaterials and nanocomposites for healthcare applications with special emphasis on the multifunctional role of inulin in cancer therapy as a synergist, signaling molecule, immunomodulatory and anticarcinogenic molecule. Furthermore, the review provides a concise overview of ongoing clinical trials and observational studies associated with inulin-based therapy. In conclusion, the current review offers insights on the significant role of inulin interventions in exploring its potential as a therapeutic agent to treat cancer.

Influence of Modified Carbon Black on Nylon 6 Nonwoven Fabric and Performance as Adsorbent Material

The number of chronic kidney disease (CKD) persons continues to rise in Mexico. They require renal replacement therapy, and in the absence of it, hemodialysis is the major option for their survival. The uremic toxins present in the blood are removed by hemodialysis, which involve membranes. In this study, nonwoven fabrics with modified carbon black nanoparticles in a matrix polymer of Nylon 6 were obtained and evaluated as an adsorbent material of uremic toxins. All nonwoven fabrics were characterized by FTIR, XRD, TGA, SEM, and contact angle measurements and were evaluated as an adsorbent material for the urea toxin and as an albumin retainer. The findings suggest their potential application as a hemodialysis membrane. Nanocomposites had a higher hydrophilic characteristic compared to pure Nylon 6. The average diameter size of the fibers was in the range of 5 to 50 μm. All nanocomposites nonwoven fabrics showed high removal percentages of inulin in a range of 80-85% at 15 min of contact. Most Ny6 Zytel/CB nanocomposites showed a high percentage of urea removal (80 to 90%).

Garlic inulin as a fat replacer in vegetable fat incorporated low-fat chicken sausages

Inulin is a non-digestible carbohydrate and a prebiotic that can also act as a fat replacer in various foods. This study examined the effect of replacing vegetable oil with garlic inulin on the quality traits of chicken sausages. Water-based inulin gels were prepared using garlic inulin or commercial inulin to imitate fats in chicken sausages. Chicken sausages were prepared separately replacing vegetable oil with water-based inulin gels to reach final inulin percentages of 1, 2, and 3 (w/w). The control was prepared using 3% (w/w) vegetable oil with no inulin. The physicochemical properties and thiobarbituric acid reactive substance (TBARS) value of prepared sausages were analyzed over 28-d frozen storage. Sausages with 2% garlic inulin recorded higher flavour and overall acceptability scores (p<0.05). Ash, moisture, and protein contents of the sausages were increased with increasing levels of inulin while fat content was reduced from 13.67% (control) to 4.47%–4.85% (p<0.05) in 3% inulin-incorporated products. Sausages incorporated with 2% inulin had lower lightness (L*) values than the control (p<0.05). Water holding capacity (WHC) was similar (p>0.05) among the samples. During storage L* value, pH, and WHC decreased while redness (a*) and yellowness (b*) values increased in all the samples. In addition, TBARS values were increased during the storage in all samples within the acceptable limits. In conclusion, garlic inulin can be used successfully as a fat substitute in sausages without altering meat quality parameters.

Inulin and Its Application in Drug Delivery

Inulin’s unique and flexible structure, stabilization/protective effects, and organ targeting ability make it an excellent drug delivery carrier compared to other biodegradable polysaccharides. The three hydroxyl groups attached to each fructose unit serve as an anchor for chemical modification. This, in turn, helps in increasing bioavailability, improving cellular uptake, and achieving targeted, sustained, and controlled release of drugs and biomolecules. This review focuses on the various types of inulin drug delivery systems such as hydrogel, conjugates, nanoparticles, microparticles, micelles, liposomes, complexes, prodrugs, and solid dispersion. The preparation and applications of the different inulin drug delivery systems are further discussed. This work highlights the fact that modification of inulin allows the use of this polymer as multifunctional scaffolds for different drug delivery systems.

Chemically modified inulin for intestinal drug delivery - A new dual bioactivity concept for inflammatory bowel disease treatment

This study investigates a novel preparation technique for pellets made from acetylated inulin and their characterization focusing on specific intestinal delivery of 5-aminosalicylic acid. By means of acetylation the hydrophobicity of four native inulins was increased yielding materials with selected degrees of acetylation. The acetylated inulins were insoluble in water, which was confirmed by the log P-values ranging from 1.30 to 1.58. 5-Aminosalicylic acid loading capacity of the pellets was up to 60 % and high enough to match the therapeutic range of the anti-inflammatory drug. Depending on the 5-aminosalicylic acid content and the type of acetylated inulin, up to 80 % of the entrapped drug was released within 24 h in intestinal environment under in-vitro conditions. Here we successfully prepared chemically modified and profoundly characterized inulin to provide innovative formulations and to open up a promising new strategy for treatment of Morbus Crohn and ulcerative colitis.

Macrophages-targeting mannosylated nanoparticles based on inulin for the treatment of inflammatory bowel disease (IBD)

In the present experimental series, we have developed a novel nanocomposite to target activated macrophages in the colon with real time imaging and therapeutic capabilities. This binary nanocomposite was formed by the covalent conjugation of mannosylated NPs (Man-NPs) with carbon dots (CDs). Man-NPs were prepared using a self-assembly method based on mannosylated decamethylenediamine-grafted carboxymethyl inulin amphiphilic acid. While, the CDs were synthesized using a simple bottom-up process using citric acid monohydrate and diethylenetriamine, which were tightly bonded to the Man-NPs surface by carbodimide coupling. The resulting nanocomposite had a uniform size of 241.3 nm with a negative charge and a high drug casing density of 25.54 wt% and blue self-fluorescence were emitted. Whereas, in vitro observation of cellular uptake indicated the greater nanocomposite uptake in inflamed macrophage as compared to the untreated macrophage and mannose receptor-negative cell lines, 4T1 respectively. However, in vivo bio distribution exhibited a large number (60%) of CDs/Man-NPs nanocomposite accumulated in the inflamed colon of colitis mice. It should be noted that the novel nanocomposite, as macrophage-targeted drug delivery, could have promise for the treatment of inflammatory bowel disease (IBD).

Hydrophobic Modification of Cashew Gum with Alkenyl Succinic Anhydride

Cashew gum (CG) shows promise of being useful as an agro-based raw material for the production of eco-friendly and biodegradable polymers. In this work, we modified this water-soluble polymer with alkenyl succinic anhydride in order to attach a hydrophobic group to it. The modification used two reagents: octenyl succinic anhydride and tetrapropenyl succinic anhydride. Reactions were conducted at 120 °C using dimethyl sulfoxide as a solvent, with conversions better than 88%. Samples with degrees of substitution (DS) between 0.02 and 0.20 were made. The resulting polymers were characterized using ¹H NMR, ¹³C NMR, FTIR, TGA, and GPC. The addition of the hydrophobe decreased the affinity of cashew gum for water absorption. Hydrophobically modified polysaccharides are often used as polymeric emulsifiers, thickeners, and compatibilizers; we anticipate that these new hydrophobically modified CGs may be used for the same applications.

Enhanced Efficacy of Immunization with a Foot-and-Mouth Disease Multi-Epitope Subunit Vaccine Using Mannan-Decorated Inulin Microparticles

BACKGROUND

Despite the many advantages of recombinant subunit vaccines, they have critical weaknesses that include a low efficacy for promoting cellular and humoral immune responses against antigens because of their poor immunogenicity, and a rapidly cleared properties as a result of proteolytic enzymes in the body. To circumvent these problems, we developed mannan-decorated inulin acetate microparticles (M-IA MPs) that functioned as carriers and adjuvants for immunization with the recombinant foot-and-mouth disease multi-epitope subunit vaccine (M5BT).

METHODS

The M5BT-loaded M-IA MPs were obtained by a double-emulsion solvent-evaporation method. Their properties including morphology, size and release ability were determined by field emission scanning electron microscope, dynamic light-scattering spectrophotometer and spectrophotometer. To assess the immunization efficacy of the MPs, mice were immunized with MPs and their sera were analyzed by ELISA.

RESULTS

The M-IA MPs obtained by a double-emulsion solvent-evaporation method were spherical and approximately 2-3 µm, and M5BT was encapsulated in the M-IA MPs. The M5BT-loaded M-IA MPs showed higher antigen-specific IgG, IgG1, IgG2a and anti-FMDV antibodies than the M5BT-loaded IA MPs and the Freund's adjuvant as a control.

CONCLUSION

The M-IA MPs showed a powerful and multifunctional polymeric system that combined two toll-like receptor agonists compared to the conventional adjuvant.

Doxorubicin-Loaded Delta Inulin Conjugates for Controlled and Targeted Drug Delivery: Development, Characterization, and In Vitro Evaluation

Delta inulin, also known as microparticulate inulin (MPI), was modified by covalently attaching doxorubicin to its nanostructured surface for use as a targeted drug delivery vehicle. MPI is readily endocytosed by monocytes, macrophages, and dendritic cells and in this study, we sought to utilize this property to develop a system to target anti-cancer drugs to lymphoid organs. We investigated, therefore, whether MPI could be used as a vehicle to deliver doxorubicin selectively, thereby reducing the toxicity of this antibiotic anthracycline drug. Doxorubicin was covalently attached to the surface of MPI using an acid–labile linkage to enable pH-controlled release. The MPI-doxorubicin conjugate was characterized using FTIR and SEM, confirming covalent attachment and indicating doxorubicin coupling had no obvious impact on the physical nanostructure, integrity, and cellular uptake of the MPI particles. To simulate the stability of the MPI-doxorubicin in vivo, it was stored in artificial lysosomal fluid (ALF, pH 4.5). Although the MPI-doxorubicin particles were still visible after 165 days in ALF, 53% of glycosidic bonds in the inulin particles were hydrolyzed within 12 days in ALF, reflected by the release of free glucose into solution. By contrast, the fructosidic bonds were much more stable. Drug release studies of the MPI-doxorubicin in vitro, demonstrated a successful pH-dependent controlled release effect. Confocal laser scanning microscopy studies and flow cytometric analysis confirmed that when incubated with live cells, MPI-doxorubicin was efficiently internalized by immune cells. An assay of cell metabolic activity demonstrated that the MPI carrier alone had no toxic effects on RAW 264.7 murine monocyte/macrophage-like cells, but exhibited anti-cancer effects against HCT116 human colon cancer cells. MPI-doxorubicin had a greater anti-cancer cell effect than free doxorubicin, particularly when at lower concentrations, suggesting a drug-sparing effect. This study establishes that MPI can be successfully modified with doxorubicin for chemotherapeutic drug delivery.

Inulin as a multifaceted (active) substance and its chemical functionalization: From plant extraction to applications in pharmacy, cosmetics and food

This review is aimed at critically discussing a collection of research papers on Inulin (INU) in different scientific fields. The first part of this work gives an overview on the main characteristics of native INU, including production, applications in food or cosmetics industries, its benefits on human health as well as its main nutraceutical properties. A particular focus is dedicated to the extraction techniques and to the specific effects of INU on intestinal microbiota. Other than in food industry, the number of INU applications increases dramatically in the pharmaceutical field especially due to its simple chemical functionalization. Thus, aim of this review is also to give practical examples of chemical functionalization performed on INU also by including critical comments based on the direct experience of the Authors. With this aim, a full paragraph is dedicated to practical chemical experiences useful to reduce the efforts when establishing new experimental conditions. Moreover, the pharmaceutical technology is also taken in special consideration by underlining the aspects leading at the preparation of formulations based on INU. At the end of the review, a critical paragraph is intended to feed the scientists' curiosity on this versatile polysaccharide.

Degradation studies of modified inulin as potential encapsulation material for colon targeting and release of mesalamine

Due to the potential to treat colon specific diseases with reduced side effects, colon targeting has become of high interest over the last decades. Chemical modified inulin was investigated for its potential as encapsulation material regarding its enzymatic degradability and its drug release behavior. Different degrees of acetylated inulin (degree of substitution, DS, 0.3-2.1) were synthesized. The chemical modification leads to a reduction in enzymatic degradability by inulinase and esterase, enzymes which can be expressed by the colon microbiota. Acetylated inulin was only hydrolyzed to fructose units up to DS of 1.3. Microparticles made of native inulin and acetylated inulin (DS 1.8) were loaded with the colon-specific drug mesalamine by spray drying. Compared to the burst release of mesalamine by inulin particles within 6 h, acetylated inulin particles showed less burst release followed by a continuous drug release phase caused by diffusion up to 30% mesalamine after 52 h.

Release Kinetic in Yogurt from Gallic Acid Microparticles with Chemically Modified Inulin

Gallic acid (GA) was encapsulated with native (NIn), cross-linked (CIn) and acetylated (AIn) inulin by spray-drying. Inulin microparticles were characterized by encapsulation efficiency (EE) and their release profile in yogurt. The EE was significantly higher for GA-CIn (98%) compared with GA-NIn (81%) and GA-AIn (77%) microparticles, showing the effect of the modification of inulin on interaction of GA-polymer. GA release profile data in yogurt for GA-CIn, GA-NIn and GA-AIn were fitted to Peppas and Higuchi models in order to obtain the GA release rate constant. Although the GA release rate constants were significantly different among systems, these differences were slight and the GA release was fast (80% < 2 h) in the three systems, showing that inulin-systems did not control GA release in yogurt. The mechanism of GA release followed a Fickian diffusion and relaxation of chains for all microparticles. According to the release profile, these microparticles would be best suited for use in instant foods.

Comparison of properties of new sources of partially purified inulin to those of commercially pure chicory inulin

Newly developed inulin powders were prepared from roots of Asparagus falcatus (AF) and Taraxacum javanicum (TJ) plants grown in Sri Lanka. Inulin content, analyzed by enzymatic spectrophotometric as well as high-performance liquid chromatographic methods, showed that AF and TJ inulin powders contain 65.5% and 45.4% (dry wt) inulin, respectively, compared with 72% dry wt in the commercially available chicory inulin. Treating the AF and TJ inulin powders using ion exchange techniques significantly (P < 0.05) reduced their contents of micro (Zn, Cu, Mn, Fe) and macro (Na, K, Ca, Mg) elements. Enzymatic hydrolysis of inulin into fructose and glucose by fructanase, and FT-IR analyses proved that the developed AF and TJ inulins have characteristic molecular composition similar to commercial inulin. TJ inulin contained significantly (P < 0.05) greater amounts of total phenolics (4.37 mg GAE/g), total flavonoids (2.79 mg QE/g), and antioxidant capacity (833.11 mM TE/g) than AF inulin, which contained 1.33 mg GAE/g of total phenolics, 0.43 mg QE/g of total flavonoids, and 406.26 mM TE/g antioxidant capacity. The current study suggests that the newly developed inulin from AF and TJ roots could be used as an alternative commercial source of inulin for the food industry.

Coacervated liposoluble fructan-based host–guest microspheres as unique drug delivery materials

A new approach to drug release with microspheres from acetylated liposoluble fructans is demonstrated. Modification of solubility by acetylation supported their preparation by precipitation–coacervation that was able to encapsulate ∼33% of ibuprofen.

Prebiotic potential of Agave angustifolia Haw fructans with different degrees of polymerization

Inulin-type fructans are the most studied prebiotic compounds because of their broad range of health benefits. In particular, plants of the Agave genus are rich in fructans. Agave-derived fructans have a branched structure with both β-(2→1) and β-(2→6) linked fructosyl chains attached to the sucrose start unit with a degree of polymerization (DP) of up to 80 fructose units. The objective of this work was to assess the prebiotic potential of three Agave angustifolia Haw fructan fractions (AFF) with different degrees of polymerization. The three fructan fractions were extracted from the agave stem by lixiviation and then purified by ultrafiltration and ion exchange chromatography: AFF1, AFF2 and AFF3 with high (3-60 fructose units), medium (2-40) and low (2-22) DP, respectively. The fructan profile was determined with high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), which confirmed a branched fructan structure. Structural elucidation was performed by Fourier Transform Infra-Red Spectroscopy. The AFF spectrum shows characteristic fructan bands. The prebiotic effect of these fractions was assessed in vitro through fermentation by Bifidobacterium and Lactobacillus strains. Four growth patterns were observed. Some bacteria did not grow with any of the AFF, while other strains grew with only AFF3. Some bacteria grew according to the molecular weight of the AFF and some grew indistinctly with the three fructan fractions.

The study of release of chlorhexidine from preparations with modified thermosensitive poly-N-isopropylacrylamide microspheres

The aim of this study was to investigate and compare the release rates of chlorhexidine (CX) base entrapped in the polymeric beads of modified poly-N-isopropylacrylamides (pNIPAMs) at temperatures below and over the volume phase transition temperature (VPTT) of synthesized polymers: pNIPAM-A with terminal anionic groups resulting from potassium persulfate initiator, pNIPAM-B with cationic amidine terminal groups, and pNIPAM-C comprising anionic terminals, but with increased hydrophobicity maintained by the N-tert-butyl functional groups. The preparations, assessed in vitro below the VPTT, release an initial burst of CX at different time periods between 120 and 240 min, followed by a period of 24 h, when the rate of release remains approximately constant, approaching the zero-order kinetics; the release rates for the polymers beads are as follows: pNIPAM-C>pNIPAM-B>pNIPAM-A. The pattern of release rates at temperature over the VPTT is as follows: pNIPAM-C>pNIPAM-A>pNIPAM-B. In the presence of pNIPAM-C, the duration between the start of the release and the attained minimal inhibitory concentration (MIC) for most of the microbes, in conditions over the VPTT, increased from 60 to 90 min. The release prolongation could be ascribed to some interactions between the practically insoluble CX particle and the hydrophobic functional groups of the polymer.

Inulin–iron complexes: A potential treatment of iron deficiency anaemia

The aim of this work was that to synthesize macromolecular derivatives based on inulin able to complex iron and useful in the treatment of iron deficiency anaemia. Carboxylated or thiolated/carboxylated inulin derivatives were obtained by single or double step reactions, respectively. The first one was obtained by reaction of inulin (INU) with succinic anhydride (SA) alone obtaining INU-SA derivative; the second one was obtained by the reaction of INU with succinic anhydride and subsequent reaction of INU-SA with cysteine; both derivatives were treated with ferric chloride in order to obtain the INU-SA-Fe(III) and INU-SA-Cys-Fe(III) complexes. Both complexes showed an excellent biodegradability in the presence of inulinase and pronounced mucoadhesion properties; in particular, thiolated derivative INU-SA-Cys showed greater mucoadhesive properties than polyacrylic acid chosen, as a positive reference polymer, and a good iron release profile in condition mimicking the intestinal tract. These results suggest the potential employment of such systems in the oral treatment of iron deficiency anaemia or as supplement of iron in foods.

UV-Photocrosslinking of Inulin Derivatives to Produce Hydrogels for Drug Delivery Application

In this work, INU, a natural polysaccharide, has been chemically modified in order to obtain new photocrosslinkable derivatives. To reach this goal, INU has been derivatized with MA thus obtaining four samples (INU-MA derivatives) as a function of the temperature and time of reaction. An aqueous solution of the derivative INU-MA1 was irradiated by using a UV lamp with an emission range from 250 to 364 nm and without using photoinitiators. The obtained hydrogel showed a remarkable water affinity but it underwent a partial degradation in simulated gastric fluid. To overcome this drawback, INU-MA1 was derivatized with SA thus obtaining the INU-MA1-SA derivative designed to produce a hydrogel showing a low swelling and an increased chemical stability in acidic medium. Ibuprofen, as a model drug, was loaded by soaking into INU-MA1 and INU-MA1-SA hydrogels and its release from these matrices was evaluated in simulated gastrointestinal fluids. INU-MA1 hydrogel showed the ability to quickly release the entrapped drug thus indicating its potential as a matrix for an oral formulation. INU-MA1-SA hydrogel showed a pH-responsive drug delivery. Therefore it is a promising candidate for controlled drug release in the intestinal tract.

Molecular properties and prebiotic effect of inulin obtained from artichoke (Cynara scolymus L.)

A high molecular weight inulin has been prepared from artichoke (Cynara scolymus L.) agroindustrial wastes using environmentally benign aqueous extraction procedures. Physico-chemical analysis of the properties of artichoke inulin was carried out. Its average degree of polymerization was 46, which is higher than for Jerusalem artichoke, chicory, and dahlia inulins. GC-MS confirmed that the main constituent monosaccharide in artichoke inulin was fructose and its degradation by inulinase indicated that it contained the expected beta-2,1-fructan bonds. The FT-IR spectrum was identical to that of chicory inulin. These data indicate that artichoke inulin will be suitable for use in a wide range of food applications. The health-promoting prebiotic effects of artichoke inulin were demonstrated in an extensive microbiological study showing a long lasting bifidogenic effect on Bifidobacterium bifidum ATCC 29521 cultures and also in mixed cultures of colonic bacteria.

Microspheres based on inulin for the controlled release of serine protease inhibitors: preparation, characterization and in vitro release

The pharmacological activity of serine protease inhibitors, potential drugs for the treatment of thrombosis, is often linked to the presence of amidine functions. With the aim of developing a suitable formulation for these compounds, inulin and inulin acetate associated or not with 1,12-dodecanedicarboxylic acid, were chosen to prepare microspheres. Using a coacervation method, these biocompatible polymers led to microspheres of about 0.5-5 microm. The encapsulation of a water-soluble model drug (E,E)-bis(amidinobenzylidene)cycloheptanone [(E,E)-BABCH] in these microspheres was studied. In this investigation, factorial designs were used to determine the joint influence of several variables (drug mass, speed and time of formulation stirring, centrifugation time) for an optimum encapsulation efficiency. Results revealed that encapsulation efficiency reached 65% whatever the nature of the biopolymer, by using a stirring time of 30 min, a high stirring speed and a centrifugation time of 15 min. (E,E)-BABCH release from microspheres was examined in an in vitro model. The profiles were characterized by three phases strongly dependent on the microspheres and the diacid association displayed a crucial role. With inulin and inulin acetate, the initial phase was a rapid 'drug burst'. Within the first 5 min, 58-62% of the drug were delivered. Microspheres of inulin acetate associated with 1,12-dodecanedicarboxylic acid, showed a slower release with only 32% of the drug delivered after 15 min. After a slow diffusion phase (33 h), an increasing rate until complete drug release was observed for 2.5 days.

A study of doxorubicin loading onto and release from sulfopropyl dextran ion-exchange microspheres

The objective of this study was to investigate various factors that influence doxorubicin (Dox) loading onto and release from sulfopropyl dextran ion-exchange microspheres (MS), and to evaluate the anticancer activity of the released drug in vitro. Dox was incorporated into the MS by incubating the MS with aqueous solutions of Dox at room temperature. The drug release was carried out at 37 degrees C in aqueous solutions containing NaCl with or without CaCl2. The kinetics of drug absorption and release, the amount of Dox released, and the stability of Dox after loading, freeze-drying, and release were determined by spectrophotometry. The cytotoxicity of Dox (the original drug or that released from MS) against murine EMT6 breast cancer cells was assessed using a clonogenic assay. An increase in the MS to drug ratio resulted in a higher absorption rate and a higher fraction of the drug extracted from the solution. The release rate and the equilibrium fraction of Dox released increased with a decrease in the initial amount of Dox loaded or an increase in the salt concentration. The addition of divalent ions (Ca2+) promoted drug release compared to NaCl alone. The percent loss of colony forming ability of the cells, a measure of cytotoxicity of the released Dox, was the same as parent Dox solutions, indicating that the drug bioactivity was fully preserved after the drug loading and release cycle. This work demonstrated that various drug release rates were achieved by varying the drug loading and that the MS-delivered Dox was effective against the cancer cells in vitro.