Formation Of Polyelectrolyte Complexes Research Articles

Methods to Enhance Mechanical Strength of 3D Printed Chitosan Scaffolds for Jawbone Regeneration

Current jaw reconstruction methods using autografts and allografts have limitations such as donor site morbidity, limited bone volume, and immunological rejection. As opposed to surgical methods synthetic biomaterials are used however they often fall short in providing the optimal combination of biocompatibility, mechanical strength, and customizable design required for effective jawbone reconstruction. 3D-printed chitosan scaffolds offer a promising alternative due to their biocompatibility, ease of customization, and potential for improved mechanical strength. This review explores strategies to optimize 3D-printed chitosan scaffolds for jaw reconstruction. We examine ways to increase their mechanical strength without compromising biocompatibility, with a particular emphasis on chemical modifications such as hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) cross-linking and chitosan polyelectrolyte complex formation. We also discuss the critical roles that 3D printing processes (FDM and SLA) and intrinsic chitosan qualities (degree of deacetylation) play in making an ink printable. Optimizing 3D printing methods for chitosan-ceramic composites and exploring biocompatible additives to enhance printability are identified as key areas for further research. By addressing these challenges, 3D-printed chitosan scaffolds have the potential to become next-generation biomaterials for jaw reconstruction, revolutionizing the field through precise anatomical adaptation, enhanced osteoconductivity, controlled biodegradation, and the capacity for incorporating bioactive molecules, ultimately leading to accelerated bone regeneration and improved functional and aesthetic outcomes.

Characteristic of Different Chitosan Types on κ-Carrageenan Polyelectrolyte Complex (PEC) Bioplastics as Food Packaging

Graphical Abstract Highlight Research The author mentioned 4 highlights from their results research This study investigates the impact of incorporating chitosan from different sources (shrimp, crab, and fish scales) with varying molecular weights on the mechanical characteristics of bioplastics used for food packaging. The present study aims to optimize the volume ratio of κ-carrageenan and chitosan to form stable polyelectrolyte complexes (PECs) for bioplastic production. This study evaluates the quality of tilapia fillets wrapped with κ-carrageenan and chitosan PEC bioplastics after 24 h storage. The present study investigates the reaction mechanism involved in the formation of polyelectrolyte complexes between κ-carrageenan and chitosan for bioplastic production. Abstract Bioplastic represents an eco-friendly alternative to synthetic plastic which can be derived from natural polysaccharides like carrageenan. κ-carrageenan is noted for its gel-forming properties making it a common raw material for bioplastics. Mechanical properties values of κ-carrageenan bioplastics are usually below standard. The addition of materials such as chitosan can enhance those properties. Chitosan-carrageenan can form polyelectrolyte complexe (PEC) through electrostatic interactions without toxic crosslinking agents. Polymer’s molecular weight is a crucial factor influencing PEC formation. Chitosan's molecular weight varies based on the raw material and extraction process. This study aims to identify the most suitable type of chitosan for food packaging bioplastics using polyelectrolyte complex (PEC) method. Three types of commercial chitosan with different molecular weights were evaluated (shrimp, crab, and fish scale chitosan). Japanese Industrial Standards (JIS) were used for characterization assessment of bioplastics such as thickness, tensile strength, water resistance, water vapor transmission, and biodegradation rate as well as additional tests including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) analysis, and Total Plate Count (TPC) on fish fillets.The findings indicated that crab chitosan-κ carrageenan PEC bioplastic exhibited optimal results with a thickness of 0.178 mm, tensile strength of 18.053 MPa, elongation at break at 211.73%, water resistance of 63.94%, Water Vapor Transmission (WVT) of 0,001456 g/m2/day, biodegradation rate of 3.358% over 7 days, and the lowest TPC in fish fillets after 24 h, increasing from 4.39 log CFU/g to 7.45 log CFU/g. Molecular weight of chitosan was shown to significantly influence the PEC bioplastics characteristics.

A novel macroporous carboxymethyl chitosan/sodium alginate sponge dressing capable of rapid hemostasis and drug delivery

Carboxymethyl chitosan (CMCS) and sodium alginate (SA), which are excellent polysaccharide-based hemostatic agents, are capable of forming polyelectrolyte complexes (PEC) through electrostatic interactions. However, CMCS/SA PEC sponges prepared by the conventional sol-gel process exhibited slow liquid absorption rate and poor mechanical properties post-swelling. In this work, a novel strategy involving freeze casting followed by acetic acid vapor treatment to induce electrostatic interactions was developed to fabricate novel PEC sponges with varying CMCS/SA mass ratios. Compared to sol-gel process sponge, the novel sponge exhibited a higher density of electrostatic interactions, resulting in denser pore walls that resist re-gelation and swelling according to FTIR, XRD, and SEM analyses. Additionally, the liquid absorption kinetics, as well as compression and tension tests, demonstrated that the novel sponge had significantly improved rapid blood absorption capacity and mechanical properties. Furthermore, in vitro coagulation and drug release studies showed that the novel sponge had a lower blood clotting index and clotting time, along with a slower drug release rate after loading with berberine hydrochloride, showcasing its potential as a rapid hemostatic dressing with controlled drug release capabilities.

Mixing Order Asymmetry in Nanoparticle-Polymer Complexation and Precipitation Revealed by Isothermal Titration Calorimetry.

In recent years, there has been a renewed interest in complex coacervation, driven by concerted efforts to offer novel experimental and theoretical insights into electrostatic charge-induced association. While previous studies have primarily focused on polyelectrolytes, proteins, or surfactants, our work explores the potential of using cerium (CeO2) and iron (γ-Fe2O3) oxide nanoparticles (NPs) to develop innovative nanomaterials. By combining various charged species, such as polyelectrolytes, charged neutral block copolymers, and coated NPs, we study a wide variety of complexation patterns and compare them using isothermal titration calorimetry, light scattering, and microscopy. These techniques confirm that the titration of oppositely charged species occurs in two steps: the formation of polyelectrolyte complexes and subsequent phase (or microphase) separation, depending on the system studied. Across all examined cases, the entropic contribution to the total free energy surpasses the enthalpic contribution, in agreement with counterion release mechanisms. Furthermore, our investigation reveals a consistent asymmetry in the reaction enthalpy associated with the secondary process, with exothermic profiles observed upon the addition of cationic species to anionic ones and endothermic profiles in the reverse case.

Polyelectrolyte gelatin-chitosan hydrogel optimized for 3D bioprinting in skin tissue engineering

Bioprinting is a promising automated platform that enables the simultaneous deposition of multiple types of cells and biomaterials to fabricate complex three-dimensional (3D) tissue constructs. Collagen-based biomaterial used in most of the previous works on skin bioprinting has poor printability and long crosslinking time. This posed an immense challenge to create 3D constructs with pre-determined shape and configuration at high throughput. Recently, the use of chitosan for wound healing applications has attracted huge attention due to its attractive traits such as its antimicrobial properties and ability to trigger hemostasis. In this paper, we optimized polyelectrolyte gelatin-chitosan hydrogel for 3D bioprinting. Modification to the chitosan was carried out via the oppositely charged functional groups from chitosan and gelatin at a specific pH of ~pH 6.5 to form polyelectrolyte complexes. The polyelectrolyte hydrogels were evaluated in terms of physical interactions within polymer blend, rheological properties (viscosities, storage and loss modulus), printing resolution at varying pressures and feed rates and biocompatibility. The polyelectrolyte gelatin-chitosan hydrogels formulated in this work was optimized for 3D bioprinting at room temperature to achieve high shape fidelity of the printed 3D constructs and good biocompatibility with fibroblast skin cells.

Polyelectrolyte complex formation of alginate and chito oligosaccharide is influenced by their proportion and alginate molecular weight

Sodium alginate (SA) and chito oligosaccharide (COS) are widely used food additives in the food industry, and exploring their interaction to form polyelectrolyte complexes (PECs) may provide insights into food development. In the present study, the effects of viscosity-average molecular weight (Mv) and relative amounts of SA on the formation of sodium alginate/chito oligosaccharide polyelectrolyte (SCP) complexes were investigated. The results showed that the electrostatic interaction between -COOH and -NH2 and the hydrogen bonding between OH, were attributed to the formation of the SCP complexes. Then the formation and properties of SCP complexes were greatly dependent on the Mv and the relative amount of SA. SA with Mv of ≥2.16 × 106 Da could form spherical SCP complexes, while the SA/COS ratio (w/w) ≥ 0.8 was not conducive to the formation of SCP complexes. Moreover, the SCP complexes were more stable in the gastric environment than in the intestinal condition. In addition, 1.73 × 107 Da was the optimal Mv of SA for SCP complexes formation. This study contributed to a comprehensive understanding of the interaction between SA and COS, and shed light on the potential application of SA and COS formulation to develop new food products.

Distribution of polyelectrolytes and counterions upon polyelectrolyte complexation

HypothesisUnderstanding polyelectrolyte complexation remains limited due to the absence of a systematic methodology for analyzing the distribution of components between the polyelectrolyte complex (PEC) and the dilute phases. ExperimentsWe developed a methodology based on NMR to quantify all components of solid-like PECs and their supernatant phases formed by mixing different ratios of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid)-sodium salt (PAA). This approach allowed for determining relative and absolute concentrations of polyelectrolytes in both phases by 1H NMR studies. Using 23Na and 35Cl NMR spectroscopy we measured the concentration of counterions in both phases. FindingsRegardless of the mixing ratio of the polyelectrolytes the PEC is charge-stoichiometric, and any excess polyelectrolytes to achieve charge stoichiometry remains in the supernatant phase. The majority of counterions were found in the supernatant phase, confirming counterion release being a major thermodynamic driving force for PEC formation. The counterion concentrations in the PEC phase were approximately twice as high as in the supernatant phase. The complete mass balance of PEC formation could be determined and translated into a molecular picture. It appears that PAH is fully charged, while PAA is more protonated, so less charged, and some 10% extrinsic PAH-Cl- pairs are present in the complex.

3D Printable Polyelectrolyte Complex‐Integrated Interpenetrating Network Hydrogels with Customizable Mechanical Strength and pH‐Responsiveness

AbstractHerein, a novel 3D printable ink designed for the fabrication of interpenetrating polymer network (IPN) hydrogels is introduced, ingeniously integrating a polyelectrolyte complex (PEC) of hyaluronic acid (HA) and chitosan (CS) with a photo‐crosslinkable P(OEGMA‐co‐EGDEMA) polymer. Initially, the carboxyl group of HA is modified with a photo‐labile ortho‐nitrobenzyl group, preventing premature PEC formation during 3D ink formulation. Subsequent UV illumination via digital light processing (DLP) simultaneously triggers the photo‐deprotection of the carboxyl group of HA and the photopolymerization of OEGMA crosslinked hydrogel, together creating a PEC‐integrated IPN hydrogel. Comprehensive characterizations, including NMR, IR, UV/Vis, TGA, DSC, SEM, and mechanical tests are conducted to evaluate the structural, morphological, and rheological properties of these hydrogels. Furthermore, adjustments to the composition of the 3D ink enable the production of hydrogels with a spectrum of mechanical strength and elastic modulus ranging from 1 to 10 kPa. The resultant PEC‐IPN hydrogels display excellent flexibility, compressive strength, high strain tolerance, pH responsiveness, and thermal stability. In essence, the approach seamlessly merges natural polyelectrolytes with technological innovation to refine 3D ink production. This method could mark a pivotal advancement in the realm of 3D materials, unlocking numerous prospective applications.

Complexation of Poly(ethylene glycol)-(ds)OligoDNA Conjugates with Ionic Liquids.

We report the complexation of poly(ethylene glycol) conjugated double-stranded oligoDNA (PEG-(ds)oligoDNA) with imidazolium-based ionic liquids (ILs) to form polyelectrolyte complex aggregates (PCAs). The PEG-(ds)oligoDNA conjugates are prepared following a solution-phase coupling reaction. The binding of PEG-(ds)oligoDNA with either 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) or 1-hexyl-3-methylimidazolium tetrafluoroborate ([HMIM][BF4]) is confirmed by a fluorescence displacement assay. Both ILs show stronger binding affinity to PEG-(ds)oligoDNA than bare (ds)oligoDNA due to the PEG-assisted increase in IL cation concentration in the vicinity of (ds)oligoDNA. The complex morphology formed at various amine (N) to phosphate (P) ratios is also examined. At high N/P ratios above 4, nanosized PCAs are formed, driven by a counterion-mediated attraction among the IL-bound (ds)oligoDNA segments and stabilized by the conjugated PEG segments. The PCAs exhibit near-neutral surface charges and resistance to DNase degradation, suggesting their potential use in gene delivery applications.

Investigation of Silk Fibroin/Poly(Acrylic Acid) Interactions in Aqueous Solution.

Silk fibroin (SF) is a protein with many outstanding properties (superior biocompatibility, mechanical strength, etc.) and is often used in many advanced applications (epidermal sensors, tissue engineering, etc.). The properties of SF-based biomaterials may additionally be tuned by SF interactions with other (bio)polymers. Being a weak amphoteric polyelectrolyte, SF may form polyelectrolyte complexes (PECs) with other polyelectrolytes of opposite charge, such as poly(acrylic acid) (PAA). PAA is a widely used, biocompatible, synthetic polyanion. Here, we investigate PEC formation between SF and PAA of two different molecular weights (MWs), low and high, using various techniques (turbidimetry, zeta potential measurements, capillary viscometry, and tensiometry). The colloidal properties of SF isolated from Bombyx mori and of PAAs (MW, overlap concentration, the influence of pH on zeta potential, adsorption at air/water interface) were determined to identify conditions for the SF-PAA electrostatic interaction. It was shown that SF-PAA PEC formation takes place at different SF:PAA ratios, at pH 3, for both high and low MW PAA. SF-PAA PEC's properties (phase separation, charge, and surface activity) are influenced by the SF:PAA mass ratio and/or the MW of PAA. The findings on the interactions contribute to the future development of SP-PAA PEC-based films and bioadhesives with tailored properties.

Polyelectrolyte complexes based on a novel and sustainable hemicellulose-rich lignosulphonate for drug delivery applications

Polyelectrolyte complexes (PECs) are polymeric structures formed by the self-assembly of oppositely charged polymers. Novel biomaterials based on PECs are currently under investigation as drug delivery systems, among other applications. This strategy leverages the ability of PECs to entrap drugs under mild conditions and control their release. In this study, we combined a novel and sustainably produced hemicellulose-rich lignosulphonate polymer (EH, negatively charged) with polyethyleneimine (PEI) or chitosan (CH, positively charged) and agar for the development of drug-releasing PECs. A preliminary screening demonstrated the effect of several parameters (polyelectrolyte ratio, temperature, and type of polycation) on PECs formation. From this, selected formulations were further characterized in terms of thermal properties, surface morphology at the microscale, stability, and ability to load and release methylene blue (MB) as a model drug. EH/PEI complexes had a more pronounced gel-like behaviour compared to the EH/CH complexes. Differential scanning calorimetry (DSC) results supported the establishment of polymeric interactions during complexation. Overall, PECs’ stability was positively affected by low pH, ratios close to 1:1, and the addition of agar. PECs with higher EH content showed a higher MB loading, likely promoted by stronger electrostatic interactions. The EH/CH formulation enriched with agar showed the best sustained release profile of MB during the first 30 h in a pH-dependent environment simulating the gastrointestinal tract. Overall, we defined the conditions to formulate novel PECs based on a sustainable hemicellulose-rich lignosulphonate for potential applications in drug delivery, which promotes the valuable synergy between sustainability and the biomedical field.Graphical abstract

Response Surface Methodology: An Optimization of Process Variables for the Nanoencapsulation of Anthocyanins from Black Rice Bran

Nanoencapsulation technology has been used in food and pharmaceutical applications to increase bioactive chemical functioning and stability against external influences. To develop a cost-effective encapsulating procedure, additional optimization is required. This study employed response surface methodology (RSM) to optimize the encapsulation of anthocyanin-rich extract from black rice bran. The extract was encapsulated through pre-gelation and polyelectrolyte complex formation processes. Box-Behnken design was employed to determine the optimum conditions for the encapsulation process with the following process variables: chitosan concentration, pH, and CaCl2 concentration. Chemical characteristics, surface morphology, and particle size were used to describe the resultant capsules, which were then subjected to phytochemical analysis. The optimal encapsulation conditions for anthocyanin were 6.30 mg/mL chitosan, pH 5.5, and 36 mM CaCl2, with a 51.20 % encapsulation efficiency. The developed anthocyanin-loaded nanocapsule has a high TPC (3.87 mg GAE/g) and potent antioxidant activity (5.69 mg TE/g). SEM images revealed a smooth surface area and spherical particles that clumped together, with an average particle size of 94.70 nm. FTIR analysis corroborates the well-incorporation of anthocyanin into the nanocapsules. The encapsulation process of anthocyanin-rich extract from black rice bran was successfully optimized via RSM.

Additive manufacturing of wet-spun chitosan/hyaluronic acid scaffolds for biomedical applications

Additive manufacturing (AM) holds great potential for processing natural polymer hydrogels into 3D scaffolds exploitable for tissue engineering and in vitro tissue modelling. The aim of this research activity was to assess the suitability of computer-aided wet-spinning (CAWS) for AM of hyaluronic acid (HA)/chitosan (Cs) polyelectrolyte complex (PEC) hydrogels. A post-printing treatment based on HA chemical cross-linking via transesterification with poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) was investigated to enhance the structural stability of the developed scaffolds in physiological conditions. PEC formation and the esterification reaction were investigated by infrared spectroscopy, thermogravimetric analysis, evolved gas analysis-mass spectrometry, and differential scanning calorimetry measurements. In addition, variation of PMVEMA concentration in the cross-linking medium was demonstrated to strongly influence scaffold water uptake and its stability in phosphate buffer saline at 37 °C. The in vitro cytocompatibility of the developed hydrogels was demonstrated by employing the murine embryo fibroblast Balb/3T3 clone A31 cell line, highlighting that PMVEMA cross-linking improved scaffold cell colonization. The results achieved demonstrated that the developed hydrogels represent suitable 3D scaffolds for long term cell culture experiments.

Preparation, Structure, and Properties of Chitosan Microtubes

Procedures were developed for forming hollow cylindrical structures with the wall thickness in the micrometer range (microtubes) from chitosan solutions in citric, lactic, and glycolic acids. The procedures are based on the phase-transfer neutralization induced by the transport of ions (hereinafter, ion-induced reaction), occurring at the liquid–liquid or solid–liquid interface, namely, on the polymer-analogous conversion of the salt form of the polymer to the base form in a NaOH or triethanolamine medium or formation of a water-insoluble polyelectrolyte complex with sodium dodecylbenzenesulfonate. Comparative analysis of the dependences of the morphological, structural, elastoplastic, physicomechanical, and biological properties of the structures on the reaction conditions and kind of the organic acid and neutralizing agent was made. The microtubes prepared from a chitosan solution in glycolic acid by ion-induced neutralization at the solid–liquid interface in a NaOH or triethanolamine medium exhibit the optimum levels of strength and elasticity, comparable with those of a fragment of human carotid artery and xenopericardial patch. The hemo- and biocompatibility and controlled biodegradation of these materials make them promising as analogs of biodegradable blood vessel implants.

Polyelectrolyte-Complex-Based Hydrogel Inserts for Vaginal Delivery of Posaconazole and Probiotics.

Worldwide, 40 to 50% of women suffer from reproductive tract infections. Most of these infections are mixed infections, are recurrent and difficult to treat with antimicrobials or antifungals alone. For symptomatic relief of infections, oral antimicrobial therapy must be combined with topical therapy. The purpose of this work is to optimize and develop a polyelectrolyte complex (PEC) of chitosan/anion for the formulation of posaconazole- and probiotic-loaded vaginal hydrogel inserts with prolonged release and significant mucoadhesion. PECs were prepared using chitosan as cationic and carrageenan, pectin and polycarbophil as anionic polymers via a lyophilization technique. PEC formation was confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry, by observing changes in its surface, physical and thermal properties. The probiotic, Lactobacillus casei, was added to the PEC during the lyophilization process and the effect on the probiotic viability was studied. The PECs were further compressed along with posaconazole to form hydrogel inserts and optimized using a 32 full-factorial design. The hydrogel inserts were assessed for swelling behavior, drug release, in vitro mucoadhesion and in vitro antifungal activity. The chitosan-pectin hydrogel insert demonstrated excellent mucoadhesion (1.25 N), sustained drug release (88.2 ± 2.4% in 8 h) and a swelling index of 154.7%. The efficacy of hydrogel inserts was evaluated using in vitro study with a co-culture of Lactobacillus casei and Candida albicans. This study revealed an increase in Lactobacilli casei count and a significant drop in the viable count of Candida albicans (4-log reduction in 24 h), indicating the effectiveness of hydrogel inserts in alleviating the fungal infection. Overall, our study demonstrated the potential of the hydrogel insert for preventing vaginal infection and restoring normal vaginal microbiota.

Instantaneous and reversible flocculation of Scenedesmus via Chitosan and Xanthan Gum complexation

An instantaneous and reversible flocculation method for Scenedesmus harvesting was developed, based on the complexation of Chitosan (CTS) and Xanthan Gum (XG). Under rapid stirring, Scenedesmus cells formed centimeter-sized flocs within 20 s using binary flocculants of 4 mg/L CTS and 16 mg/L XG. These flocs exhibited a remarkable harvest efficiency exceeding 95 % when filtered through 500-μm-pore-sized sieves. Furthermore, the flocs could be completely disintegrated by using alkaline or NaCl solutions (pH > 11 or NaCl concentration > 1.5 mol/L). Adjusting pH allowed recovery of 50 % CTS and 75 % XG, resulting in microalgae biomass with lower flocculant content and reducing reagent costs. Electrostatic interaction of –COO– of XG and –NH3+ of CTS deduced the formation of polyelectrolyte complexes (PECs), which shrink and wrap the coexisting algal cells to form the flocs under stirring. CTS and XG complexation was instantaneous and reversible, explaining quick flocculation and disintegration.

Design, Development, and In vitro Evaluation of Single Unit Hydrodynamically Balanced System of Captopril

Background: This study investigated the use of in situ polyelectrolyte complex formation by using two oppositely charged polysaccharides [Chitosan (cationic), Sodium Alginate (anionic)]. It forms 3-D intercalation and interpenetrating network helping in controlling the release of highly acid-soluble Captopril. Objective: To develop a polyelectrolyte complex based single unit gastroretentive tablet by using optimization based 3 (2) Taguchi factorial design for controlled delivery of Captopril. Materials and Methods: Gastroretentive Captopril tablets were prepared by the direct compression technique. Total 09 batches were prepared as per 3 (2) Taguchi factorial design studies of 100 tablets each. Results: Thermal analysis method revealed that there is a formation of PEC between chitosan and sodium alginate. In vitro buoyancy and T60%, drug release studies revealed that due to complex formation, formulation remains stable and remains buoyant. From factorial design studies, it was interpreted that for buoyancy time (Y1) chitosan desired effect value was found higher. For 60% drug release (T60%; Y2) both chitosan and sodium alginate have a synergistic effect. Durbin Watson's statistical model and residual data suggested that the model is statistically validated. All formulations follow the zero-order kinetics. Stability studies revealed that formulations F5 and F9 remain stable for long-term stability studies without showing any significant changes. The fit analysis studies indicated that the prepared formulation was different from the innovator product indicating low f1 and f2 values. Conclusion: From the result generated it was concluded that chitosan-sodium alginate polyelectrolyte complex has sufficient potential to retard the release of CPT.

Ascorbic acid nanoencapsulation using polyelectrolyte complex formation and optimization using hybrid artificial neural network‐genetic algorithm

AbstractBackgroundsThe polyelectrolyte complex (PEC) formation using chitosan (Cs) and alginate (Alg) has been employed to carry out Vitamin C (VC) nanoencapsulation because of its instability in adverse conditions. This method includes VC nanoencapsulation using physical cross‐linking. The effect of the mixing order as well as the different mass ratios of both the polymer and the VC content, were investigated on the size, pdi, zeta potential, encapsulation efficiency (EE%), and yield%. Hence, considering different mass ratios of both polymer (4:1–1:4) and VC content (10%–30% w/w of Cs) as independent variables, PECs were formed using 0.1% (w/v) of Cs and Alg solution.ResultThe result showed that, for equal mass ratio (1:1) of Cs and Alg, the addition of Alg solution to Cs solution led to lower particle size, while higher particle size was observed with reverse order of addition. However, no significant effect of polymer mass ratios was observed on particle size and NPs stability, while EE varied with VC concentration. Artificial neural network (ANN) was applied to train the experimental parameters Cs: Alg ratios (X1:X2) and VC content (X3) for the output variables. Moreover, process optimization was carried out using multi‐objective genetic algorithm (MOGA) with the goal of lowering particle size and increasing EE while increasing nanoparticle yield.ConclusionThe PEC method effectively encapsulated VC as obtained from higher EE. The Cs: Alg ratio of 4:2.1 and 18% VC content (w/w of Cs) was found optimum for nanoencapsulation. The final ANN‐GA model showed an acceptable agreement with experimental data.

Effect of ScCO2 on the decontamination of PECs-based cryogels: A comparison with H2O steam and H2O2 nebulization methods

Biopolymers present ideal properties to be used in wound dressing solutions. By mixing two oppositely charged macromolecules it is possible to form polyelectrolyte complex (PEC) based cryogels using lyophilization. Their application in the biomedical field is limited due to their sterilization requirements, as conventional methods compromise their physicochemical properties. ScCO2 appears as an alternative method for decontamination. This work assessed several cryogel PEC formulations, chitosan-pectin, gelatine-xanthan gum and alginate-gelatine. PEC formation was confirmed by FTIR and rheological analysis. While steam sterilization compromised cryogels’ chemical and morphological properties, decontamination with scCO2 proved to be a promising method for decontamination of PEC-cryogels, because, similarly to what is observed with hydrogen peroxide, it does not compromise their physicochemical properties.

Taste-Masked Flucloxacillin Powder Part 2: Formulation Optimisation Using the Mixture Design Approach and Storage Stability.

Flucloxacillin is prescribed to treat skin infections but its highly bitter taste is poorly tolerated in children. This work describes the application of the D-optimal mixture experimental design to identify the optimal component ratio of flucloxacillin, Eudragit EPO and palmitic acid to prepare flucloxacillin taste-masked microparticles that would be stable to storage and would inhibit flucloxacillin release in the oral cavity while facilitating the total release of the flucloxacillin load in the lower gastrointestinal tract (GIT). The model predicted ratio was found to be very close to the stoichiometric equimolar component ratio, which supported our hypothesis that the ionic interactions among flucloxacillin, Eudragit EPO and palmitic acid underscore the polyelectrolyte complex formation in the flucloxacillin taste-masked microparticles. The excipient-drug interactions showed protective effects on the microparticle storage stability and minimised flucloxacillin release at 2 min in dissolution medium. These interactions had less influence on flucloxacillin release in the dissolution medium at 60 min. Storage temperature and relative humidity significantly affected the chemical stability of the microparticles. At the preferred storage conditions of ambient temperature under reduced RH of 23%, over 90% of the baseline drug load was retained in the microparticles at 12 months of storage.