Physical properties and loading capacity of starch-based microparticles crosslinked with trisodium trimetaphosphate

Cross-linked modification of tapioca starch by sodium Trimetaphosphate: An influence on its structure

This study aimed to examine the changes in the structural characterization of cross-linked tapioca treated with sodium trimetaphosphate(STMP). The degree of substitution in the cross-linked starch was determined by the iodine absorption method. Scanning electron microscopy, particle size measurement, Fourier-transform infrared spectroscopy (FT-IR), and x-ray diffraction (XRD) were used to characterize the structure of modified tapioca starch at different substitution degrees. The results demonstrated that the degree of substitution of cross-linked starch increased with the increase in the amount of the cross-linking agent. The modified starch particles aggregated to form a mass structure, but the average particle size did not change with the cross-linker content and was about 17 μm. FT-IR and XRD experiments showed that the cross-linking esterification of starch with sodium trimetaphosphate generated new phosphate groups, increasing the content of phosphoric acid in starch, and the A-type crystalline structure of starch was not changed.

Sustained release, antimicrobial, and antioxidant properties of modified porous starch-based biodegradable polylactic acid/polybutylene adipate-co-terephthalate/thermoplastic starch active packaging film

Porous starch (PS) is a modified starch with commendable biodegradable and adsorption properties. PS exhibits poor thermal stability, and the aqueous solution casting method is conventionally used for PS-activated packaging films. This approach limits the large-scale production of films and makes it difficult to play the functions of porous pores. In this study, PS was prepared by enzymatic digestion combined with freeze-drying and adsorbed with clove essential oil (CEO) after cross-linking with sodium trimetaphosphate. Subsequently, a novel PLA/PBAT/TPS/ScPS-CEO sustained release active packaging film was prepared by blending PLA, PBAT, TPS, and ScPS-CEO using industrial melt extrusion. Compared with PS, ScPS effectively slowed down the release of CEO from the film, with the maximum release of active substances at equilibrium increasing by approximately 100 %, which significantly enhanced the persistence of the antimicrobial and antioxidant properties. The polylactic acid/poly (butylene adipate-co-terephthalate)/thermoplastic starch/trimetaphosphate-crosslinked porous starch incorporated with clove essential oil (PLA/PBAT/TPS/ScPS-CEO) film could reduce the proteolysis, lipid oxidation and microbial growth of salmon, extending its shelf life by approximately 100 % at 4 °C. These results indicate that the ScPS can be used in fresh packaging material in practical applications.

Effects of crosslinking with sodium trimetaphosphate on structural, physicochemical, rheological and in vitro digestibility properties of purple sweet potato starch

Purple sweet potato starch (PSPS) was modified using different amounts of sodium trimetaphosphate (0, 3-12%). Phosphorus content, crosslinking (CL), and substitution levels increased after modification. CL led to gradual agglomeration with each other through adhesion, compared to 0% STMP. X-ray diffraction did not change, but crystalline properties, swelling index, and peak viscosity increased, and solubility and glycaemic index decreased after crosslinking. Crosslinking increased, leading to a decrease of greater significance at 3% CL. Resistant starch was increased from 60.51 to 83.32%. G' and G'' values for crosslinking starch samples varied from 3086.00-5507.50 Pa and 513.92-800.30 Pa, respectively, after sweep test. The flow behavior index < 1 indicates that CL starch pastes are shear-thin. Positive and negative correlations were observed between gelatinized starch enthalpy and RS and between SDS and GI, respectively. The results lay the groundwork to comprehend the properties and relationships of CLPSPS and promote its possible use in foods.

Novel resorbable bone wax containing β-TCP and starch microspheres for accelerating bone hemostasis and promoting regeneration

Traditional non-resorbable bone wax has been used in clinical surgery for more than 100 years. However, residual bone wax has been proven to cause numerous complications. In this study, a novel resorbable bone wax was designed to overcome the disadvantages of traditional non-resorbable bone wax. Alkylene oxide copolymers were used as the main component of resorbable bone wax; additionally, β-tricalcium phosphate and starch microspheres were added to enhance bone regeneration and hemostatic ability. This novel resorbable bone wax has a high potential for clinical translation and is expected to be developed as a substitute for traditional bone wax.

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.

Development of cress seed gum hydrogel and investigation of its potential application in the delivery of curcumin

BACKGROUND

Bioactive compound delivery systems must provide stability against severe food processing and environmental conditions. Cress seed gum (CSG) with high thermal stability can be a promising polysaccharide for preparing physically cross-linked hydrogel as a curcumin delivery system. In the present study, CSG (0.05, 0.10 and 0.15 g kg^-1 ) and calcium chloride (CaCl₂ ) (0.00, 0.02, 0.04, 0.06 and 0.10 g kg^-1 ) solutions were used for hydrogel fabrication.

RESULTS

Physicochemical properties of hydrogels were evaluated by entrapment efficiency, loading capacity and swelling degree, differential scanning calorimetry, scanning electron microscopy, in vitro release and free radical scavenging capacity assessments. Accordingly, 0.15 g kg^-1 CSG-0.02 g kg^-1 CaCl₂ hydrogel was revealed to have high entrapment efficiency (93.6 ± 1.59%), loading capacity (0.92 ± 0.00%) and swelling degree (105.96 ± 12.99%), as well as heat stability above 103 °C. CSG hydrogel significantly (P < 0.05) protected the antioxidant activity of curcumin against thermal process. The curcumin release in the acidic stomach medium was negligible, although it increased significantly in the simulated intestinal environment (42.5 ± 0.75%), which followed the Peppas model.

CONCLUSION

As a result, CSG hydrogel can protect curcumin during food thermal processing and digestion time. Therefore, CSG hydrogel can play a valued role in modern-day food formulations with an increasing consumer preference for plant-derived materials. © 2021 Society of Chemical Industry.

Xylan microparticles for controlled release of mesalamine: Production and physicochemical characterization

Xylan extracted from corn cobs was used to produce mesalamine-loaded xylan microparticles (XMP5-ASA) by cross-linking polymerization using a non-hazardous cross-linking agent. The microparticles were characterized by thermal analysis (DSC/TG), X-ray diffraction (XRD), Infrared spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM). A comparative study of the in vitro drug release from XMP5-ASA and from gastro-resistant capsules filled with XMP5-ASA (XMPCAP5-ASA) or 5-ASA was also performed. NMR, FTIR-ATR, XRD and DSC/TG studies indicated molecularly dispersed drug in the microparticles with increment on drug stability. The release studies showed that XMPCAP5-ASA allowed more efficient drug retention in the simulated gastric fluid and a prolonged drug release lasting up to 24 h. XMPCAP5-ASA retained approximately 48 % of its drug content after 6 h on the drug release assay. Thus, the encapsulation of 5-ASA into xylan microparticles together with gastro-resistant capsules allowed a better release control of the drug during different simulated gastrointestinal medium.

Polymeric hydrogels as a vitreous replacement strategy in the eye

Vitreous endo-tamponades are commonly used in the treatment of retinal detachments and tears. They function by providing a tamponading force to support the retina after retina surgery. Current clinical vitreous endo-tamponades include expansile gases (such as sulfur hexafluoride (SF₆) and perfluoropropane (C₃F₈)) and also sislicone oil (SiO). They are effective in promoting recovery but are disadvantaged by their lower refractive indices and lower densities as compared to the native vitreous, resulting in immediate blurred vision after surgery and necessitating patients to assume prolonged face-down positioning respectively. While the gas implants diffuse out over time, the SiO implants are non-biodegradable and require surgical removal. Therefore, there is much demand to develop an ideal vitreous endo-tamponade that can combine therapeutic effectiveness with patient comfort. Polymeric hydrogels have since attracted much attention due to their favourable properties such as high water content, high clarity, suitable refractive indices, suitable density, tuneable rheological properties, injectability, and biocompatibility. Many design strategies have been employed to design polymeric hydrogel-based vitreous endo-tamponades and they can be classified into four main strategies. This review seeks to analyse these various strategies and evaluate their effectiveness and also propose the key criteria to design successful polymeric hydrogel vitreous endo-tamponades.

Water-in-Water Emulsion as a New Approach to Produce Mesalamine-Loaded Xylan-Based Microparticles

The water-in-water emulsion method has been reported as a technique able to prepare microparticles without using harmful solvents. However, there are few reports showing the encapsulation of small molecules into microparticles produced within this technique. The probable reason relays on the rapid diffusion of these molecules from the discontinuous phase to the continuous phase. In the present study, xylan microparticles containing mesalamine were produced and the doubled crosslinking approach, used to promote higher encapsulation rates, was disclosed. To achieve this goal, a 23 full factorial design was carried out. The results revealed that all formulations presented spherical-shaped microparticles. However, at specific conditions, only few formulations reached up to 50% of drug loading. In addition, the new xylan-based microparticles formulation retained almost 40% of its drug content after 12 h of a dissolution assay likely due to the degree of crosslinking. Thus, the doubled crosslinking approach used was effective on the encapsulation of mesalamine and may pave the way to successfully produce other polysaccharide-based carriers for clinical use.

Theoretical Insights into Three Types of Oxidized Starch-Based Adhesives: Chemical Stability, Water Resistance, and Shearing Viscosity from a Molecular Viewpoint

To better understand the origin and difference associated with chemical stability, water resistance, and shearing viscosity of three types of different oxidized modified starch-based adhesives, a detailed theoretical investigation from a molecular viewpoint has been performed using the AM1 semiempirical level and the DFT-B3LYP level, respectively. As a result, our findings suggest that, by Mulliken population analysis (MPA), frontier orbital analysis, and electrostatic potential (EP) analysis based on B3LYP/6-31G calculations, the chemical stability, water resistance, and shearing viscosity of the oxidized modified starch-based adhesives are uniformly improved and corresponding difference for each property presents an identical order: the oxidized grafted cross-linked starch-based adhesive > the oxidized grafted starch-based adhesive > the oxidized starch-based adhesive, which is well consistent with experimental results.

Preparation of cationic starch microspheres and study on their absorption to anionic-type substance

Cationic starch microspheres (CSMs) were prepared from lab-made neutral starch-based microspheres using a cationic adsorbent, namely 3-chloro-2-hydroxypropyltrimethyl ammonium chloride, as the cationic etherifying agent. Detection by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and laser diffraction techniques revealed that CSMs had coarse surfaces with good sphericity and dispersibility. Differential thermal analysis showed the lower thermostability of the CSMs' main chains. Furthermore, scores of experiments confirmed that CSMs are capable of absorption to N-(phosphonomethyl) iminodiacetic acid (PMIDA), a type of anionic substance, which is the intermediate to the preparation of glyphosate, maximally up to 95.24 mg/g. Compared with the Freundlich isotherm model, the Langmuir isotherm model can better describe the absorption process. The kinetic study showed that the pseudo-second-order model demonstrated a better correlation of the experimental data in contrast with the pseudo-first-order model. It can be therefore concluded that the rate-limiting step was the chemical absorption rather than the mass transport.