Microcrystalline cellulose, lactose and lignin blends: Process mapping of dry granulation via roll compaction

Rational Function-Based Approach for Integrating Tableting Reduced-Order Models with Upstream Unit Operations: Dry Granulation Case Study

We present a systematic and automatic approach for integrating tableting reduced-order models with upstream unit operations. The approach not only identifies the upstream critical material attributes and process parameters that describe the coupling to the first order and, possibly, the second order, but it also selects the mathematical form of such coupling and estimates its parameters. Specifically, we propose that the coupling can be generally described by normalized bivariate rational functions. We demonstrate this approach for dry granulation, a unit operation commonly used to enhance the flowability of pharmaceutical powders by increasing granule size distribution, which, inevitably, negatively impacts tabletability by reducing the particle porosity and imparting plastic work. Granules of different densities and size distributions are made with a 10% w/w acetaminophen and 90% w/w microcrystalline cellulose formulation, and tablets with a wide range of relative densities are fabricated. This approach is based on product and process understanding, and, in turn, it is not only essential to enabling the end-to-end integration, control, and optimization of dry granulation and tableting processes, but it also offers insight into the granule properties that have a dominant effect on each of the four stages of powder compaction, namely die filling, compaction, unloading, and ejection.

Determining the Impact of Roller Compaction Processing Conditions on Granulate and API Properties: Impact of Formulation API Load

Previous work demonstrated that roller compaction of a 40%w/w theophylline-loaded formulation resulted in granulate consisting of un-compacted fractions which were shown to constitute between 34 and 48%v/v of the granulate dependent on processing conditions. The active pharmaceutical ingredient (API) primary particle size within the un-compacted fraction was also shown to have undergone notable size reduction. The aim of the current work was to test the hypothesis that the observations may be more indicative of the relative compactability of the API due to the formulation being above the percolation threshold. This was done by assessing the impact of varied API loads in the formulation on the non-granulated fraction of the final granulate and the extent of attrition of API particles within the non-granulated fraction. The influence of processing conditions for all formulations was also investigated. The results verify that the observations, both of this study and the previous work, are not a consequence of exceeding the percolation threshold. The volume of un-compacted material within the granulate samples was observed to range between 34.7 and 65.5% depending on the API load and roll pressure, whilst the API attrition was equivalent across all conditions.

The effect of excipient particle size on the reduction of compactibility after roller compaction

Developing a robust roller compaction process can be challenging, due to the diversity in process parameters and material properties of the components in a formulation. A major challenge in dry granulation is the reduction of tablet strength as a result of re-compaction of the materials. The aim of this study is to investigate the impact of excipient type and particle size distribution on tablet tensile strength after roller compaction. Lactose monohydrate, anhydrous lactose and microcrystalline cellulose with different particle sizes are roller compacted at varying specific compaction forces. Granules obtained are compressed into tablets to evaluate the reduction in tablet strength upon increasing the specific compaction force. The impact of particle size of the starting material is shown to be vastly different for the three types of excipients investigated, due to the differences in mechanical deformation mechanisms. The presence of rough surfaces and a high degree of fragmentation for anhydrous lactose appears to be beneficial for compaction and re-compaction process. Additionally, the particle size of anhydrous lactose hardly affects the tensile strength of tablets, which can be beneficial for the robustness of a roller compaction process.

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The impact of particle size on the re-compactibility differs per excipient type.

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Re-compactibility is classified and quantified for different excipients.

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Rough surfaces and a high degree of fragmentation are beneficial for re-compaction.

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The particle size of anhydrous lactose hardly affects the re-compactibility.

The Practical Utility of Imidazolium Hydrogen Sulfate Ionic Liquid in Fabrication of Lignin-Based Spheres: Structure Characteristic and Antibacterial Activity

In this study, lignin-based spherical particles (Lig-IL) with the use of 1-(propoxymethyl)-1H-imidazolium hydrogen sulfate were prepared in different biopolymer and ionic liquid (IL) weight ratios. The application of IL during the preparation of spherical particles is an innovative method, which may be beneficial for further applications. The particles were obtained with the use of the soft-templating method and their chemical, structural and morphological characterization was performed. The spherical shape of products and their size (91–615 nm) was confirmed with the use of scanning electron microscopy (SEM) images and the particle size distribution results. The attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra were analyzed to identify functional groups of all precursors and produced material and it was confirmed, that all materials exhibit characteristic hydroxyl and carboxylic groups, but the presence of carbonyl group was detected. Moreover, the zeta potential analysis was performed to evaluate the electrokinetic behavior of obtained materials. It was confirmed, that all materials are colloidally stable in pH above 4. Produced lignin-based spherical particles were used for evaluation of their antibacterial properties. Particles were tested against Staphylococcus aureus (S. aureus), a gram-positive bacterium, and Escherichia coli (E. coli), a gram-negative one. It was observed, that only the material with the highest addition of IL showed the antibacterial properties against both strains. A reduction of 50% in the number of microorganisms was observed for particles with the addition of hydrogen sulfate ionic liquid in a 1:1 ratio after 1 h. However, all prepared materials exhibited the antibacterial activity against a gram-positive bacterium.

Supply Chain Design for Blending Technologies

When optimizing blending technologies, the main objective is to determine the right mixing ratio of the raw materials, depending on the different qualities and costs of the raw materials available. It can be concluded that research is mainly focused on answering technological questions, and only very few studies take into account the logistics processes related to blending technologies, their design, cost-efficiency, utilization and sustainability including energy efficiency and environmental impact. Based on this fact, within the frame of this research the authors describe a new approach, extending the basic model of blending problems by adding new supply chain efficiency-related components that makes it possible to take logistics parameters related to the raw materials supply (available stocks, batch sizes, transport and storage costs, supply chain structure) into consideration. A mathematical model of this supply chain optimization problem for blending technologies is described including routing and assignment problems in the supply chain, while technological objectives are also taken into consideration as technological objective functions and constraints. The optimization problem described in the model is a problem with non-deterministic polynomial-time hardness (NP-hard), which means that there are no known efficient analytical methods to solve the logistics-related supply chain optimization of blending technologies. As a solution algorithm, the authors have used an evolutive solver and a new metrics, which improved the efficiency of the comparison of distances between solutions of routing problems represented by permutation arrays. The scenario analysis, which focuses on the integrated optimization of technological and logistics problems validates the model and evaluates the solution algorithm and the new metrics. Using the mentioned algorithm, the supply chain processes of the blending technologies can be improved from availability, efficiency, sustainability point of view.

System model driven selection of robust tablet manufacturing processes based on drug loading and formulation physical attributes

Mechanistic process modelling presents an opportunity to reduce experimental burden, enabling relationships between process parameters and product attributes to be mapped out using in-silico experiments. A system model of a pharmaceutical tablet manufacturing process comparing dry granulation with direct compression is developed to answer key material and process design questions. The system model links API physical properties and formulation to process parameters to map out the robust operating space. To demonstrate the application of the model, several drug product formulation design questions were considered: •Which processing route is the most robust given the API material properties and dosage requirements?;• How does drug loading and tablet size impact the robustness of the manufacturing process?; •What process settings are required for a robust manufacturing route for the API material properties and drug loading requirements?; A computational framework was developed using the system models to generate process classification and design space maps to aid robust pharmaceutical formulation and process decision making. Process classification maps were produced to assess the feasibility of roller compaction and direct compression for different material properties and formulations. Constraints on the critical quality attributes of the intermediate and final products were defined using the Manufacturing Classification System. Design space maps presented here demonstrate how system models can be used to support formulation and process design. The design space maps illustrate how the process operating space can be increased or decreased as the API mass fraction is varied.; The process design and selection system model demonstrate how an understanding of the API physical properties can be used to model the impact of formulation and process design. Furthermore, these models can be instrumental in the dialogue with colleagues developing the API in order to set the requirements of the API physical properties to ensure successful and robust formulation and process designs.

State-of-art review on preparation, surface functionalization and biomedical applications of cellulose nanocrystals-based materials

Cellulose nanocrystals (CNCs) are a class of sustainable nanomaterials that are obtained from plants and microorganisms. These naturally derived nanomaterials are of abundant hydroxyl groups, well biocompatibility, low cost and biodegradable potential, making them suitable and promising candidates for various applications, especially in biomedical fields. In this review, the recent advances and development on the preparation, surface functionalization and biomedical applications of CNCs-based materials have been summarized and outlined. The main context of this paper could be divided into the following three parts. In the first part, the preparation strategies based on physical, chemical, enzymatic and combination techniques for preparation of CNCs have been summarized. The surface functionalization methods for synthesis CNCs-based materials with designed properties and functions were outlined in the following section. Finally, the current state about applications of CNCs-based materials for tissue engineering, medical hydrogels, biosensors, fluorescent imaging and intracellular delivery of biological agents have been highlighted. Moreover, current issues and future directions about the above aspects have also pointed out and discussed. We believe this review will attract great research attention of scientists from materials, chemistry, biomedicine and other disciplines. It will also provide some important insights on the future development of CNCs-based materials especially in biomedical fields.

Simultaneous surface functionalization and drug loading: A novel method for fabrication of cellulose nanocrystals-based pH responsive drug delivery system

Herein, a novel strategy for surface functionalization and drug loading of cellulose nanocrystals (CNCs) through formation of hydrazone bonds between functionalized CNCs and aldehyde group containing polyethylene glycol (CHO-PEG)/anticancer drug doxorubicin (DOX) was reported for the first time. DOX could be loaded on PEGylated CNCs with high capacity and released from drug complexes (P-CNCs-D) with pH dependent behavior. The biological evaluation results demonstrated that drug carriers (CNCs-EBO-NH) showed negative cytotoxicity while DOX could be transported into cells and exhibits desirable anticancer effects. As compared with other method, the method developed in this work is rather simple and effective and can be achieved for simultaneous for surface functionalization and drug loading in a one-pot route. This work will open a new avenue for fabrication of various multifunctional composites based on other carbohydrate polymers or materials and to explore their applications in biomedical fields.

Continuous Twin Screw Granulation: A Review of Recent Progress and Opportunities in Formulation and Equipment Design

Continuous twin screw wet granulation is one of the key continuous manufacturing technologies that have gained significant interest in the pharmaceutical industry as well as in academia over the last ten years. Given its considerable advantages compared to wet granulation techniques operated in batch mode such as high shear granulation and fluid bed granulation, several equipment manufacturers have designed their own manufacturing setup. This has led to a steep increase in the research output in this field. However, most studies still focused on a single (often placebo) formulation, hence making it difficult to assess the general validity of the obtained results. Therefore, current review provides an overview of recent progress in the field of continuous twin screw wet granulation, with special focus on the importance of the formulation aspect and raw material properties. It gives practical guidance for novel and more experienced users of this technique and highlights some of the unmet needs that require further research.

Improved Manufacturability and In Vivo Comparative Pharmacokinetics of Dapagliflozin Cocrystals in Beagle Dogs and Human Volunteers

Dapagliflozin (DAP), which improves glycemic control in patients with type 2 diabetes mellitus, has poor physical properties against heat and moisture, thus hindering its manufacturing potential. The superior physicochemical properties of a recently developed cocrystal of DAP and citric acid (DAP cocrystal) in comparison with those of DAP and Forxiga^®, a patented solvate form with propandiol monohydrate, were identified via structural analysis and moisture sorption isotherm. For the first time, the formulation, manufacturability, and in vivo bioavailability of DAP cocrystals were successfully investigated to develop oral dosage forms that substitute Forxiga^®. The intrinsic dissolution rate of DAP cocrystal was controlled by varying particle size distribution. Unlike the direct compression (DC), roller compaction (RC) was more preferable to obtain good flowability of dry granules for a continuous manufacturing system. The cocrystal structure was maintained throughout the stability assessment period. In Vitro dissolution pattern differences of the optimized DAP cocrystal tablet with RC and the reference tablet, Forxiga^® 10 mg, were pharmaceutically equivalent within 5% in four different media. Furthermore, comparative pharmacokinetic analysis confirmed that a 10 mg DAP cocrystal tablet with RC was bioequivalent to a 10 mg Forxiga^® tablet, as assessed in beagle dogs and human volunteers.

Lignin for Bioeconomy: The Present and Future Role of Technical Lignin

Lignin, the term commonly used in literature, represents a group of heterogeneous aromatic compounds of plant origin. Protolignin or lignin in the cell wall is entirely different from the commercially available technical lignin due to changes during the delignification process. In this paper, we assess the status of lignin valorization in terms of commercial products. We start with existing knowledge of the lignin/protolignin structure in its native form and move to the technical lignin from various sources. Special attention is given to the patents and lignin-based commercial products. We observed that the technical lignin-based commercial products utilize coarse properties of the technical lignin in marketed formulations. Additionally, the general principles of polymers chemistry and self-assembly are difficult to apply in lignin-based nanotechnology, and lignin-centric investigations must be carried out. The alternate upcoming approach is to develop lignin-centric or lignin first bio-refineries for high-value applications; however, that brings its own technological challenges. The assessment of the gap between lab-scale applications and lignin-based commercial products delineates the challenges lignin nanoparticles-based technologies must meet to be a commercially viable alternative.

Lignin-Based Micro- and Nanomaterials and their Composites in Biomedical Applications

Lignin, as the most abundant aromatic renewable biopolymer in nature, has long been regarded as waste and simply discarded from the pulp and paper industry. In recent years, with many breakthroughs in lignin chemistry, pretreatment, and processing techniques, a lot of the inherent bioactivities of lignin, including antioxidant activities, antimicrobial activities, biocompatibilities, optical properties, and metal-ion chelating and redox activities, have been discovered and this has opened a new field not only for lignin-based materials but also for biomaterials. In this Review, the biological activities of lignin and drug/gene delivery and bioimaging applications of various types of lignin-based material are summarized. In addition, the challenges and limitations of lignin-based materials encountered during the development of biomedical applications are also discussed.

Balancing the decomposable behavior and wet tensile mechanical property of cellulose-based wet wipe substrates by the aqueous adhesive

With the current global outbreak of novel coronaviruses, the fabrication of decomposable wet wipe with sufficient wet strength to meet daily use is promising but still challenging, especially when renewable cellulose was employed. In this work, a decomposable cellulose-based wet wipe substrate is demonstrated by introducing a synthetic N-vinyl pyrrolidone-glycidyl methacrylate (NVP-GMA) adhesive on the cellulose surface. Experimental results reveal that the NVP-GMA adhesive not only significantly facilitates the chemical bonding between cellulose fibers in the wet state, but also increase the surface wettability and water retention. The as-fabricated cellulose-based wet wipe substrate displays a superb water retention capacity of 1.9 times, an excellent water absorption capacity (completely wetted with 0° water contact angle), and a perfect wet tensile index of 3.32 N.m.g⁻¹. It is far better than state-of-the-art wet toilet wipe on the market (non-woven). The prepared renewable and degradable cellulose-based substrate with excellent mechanical strength has potential application prospects in diverse commercially available products such as sanitary and medical wet wipes.

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A decomposable wet wipe substrate was prepared from the bio-based materials.

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Synthetic adhesive enhanced the wet strength of the cellulose sheet.

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Enhancement of cellulose-based material was achieved under aqueous conditions.

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As-prepared cellulose substrate balanced the dispersibility and wet strength.

Determining the Impact of Roller Compaction Processing Conditions on Granule and API Properties

The attrition of drug particles during the process of dry granulation, which may (or may not) be incorporated into granules, could be an important factor in determining the subsequent performance of that granulation, including key factors such as sticking to punches and bio-performance of the dosage form. It has previously been demonstrated that such attrition occurs in one common dry granulation process train; however, the fate of these comminuted particles in granules was not determined. An understanding of the phenomena of attrition and incorporation into granule will improve our ability to understand the performance of granulated systems, ultimately leading to an improvement in our ability to optimize and model the process. Unique feeding mechanisms, geometry, and milling systems of roller compaction equipment mean that attrition could be more or less substantial for any given equipment train. In this work, we examined attrition of API particles and their incorporation into granule in an equipment train from Gerteis, a commonly used equipment train for dry granulation. The results demonstrate that comminuted drug particles can exist free in post-milling blends of roller compaction equipment trains. This information can help better understand the performance of the granulations, and be incorporated into mechanistic models to optimize such processes.

VS2 and its doped composition: Catalytic depolymerization of alkali lignin for increased bio-oil production

VS₂ spheres and VS₂ sheets with doped compositions (Mo, Ag and graphite) were successfully prepared by one-step hydrothermal method and characterized by different techniques including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ adsorption isotherms. Catalysts were applied for the depolymerization of alkali lignin. VS₂ spheres exhibited lower yield of degraded lignin and bio-oil than those with VS₂ sheets and VS₂ flowers heated to 250 °C and held for 1.5 h with 2.0 MPa H₂. The catalytic depolymerization performance was markedly affected by the dopant in the VS₂ sheets, with the highest degraded lignin yield of 81.22%, achieved over 5 wt% Ag-VS₂ at 290 °C under 2.0 MPa H₂ for 1.5 h, yielding 61.23% bio-oil. The VS₂-based catalysts show excellent selectivity in the interruption of the lignin structure and target production of bio-oil. The bio-oil showed that the relevant contents of a phenolic-type compound changes significantly according to the dopant in the VS₂ catalyst.

Electrospun cellulose acetate/gelatin nanofibrous wound dressing containing berberine for diabetic foot ulcer healing: in vitro and in vivo studies

Functional wound dressing with tailored physicochemical and biological properties is vital for diabetic foot ulcer (DFU) treatment. Our main objective in the current study was to fabricate Cellulose Acetate/Gelatin (CA/Gel) electrospun mat loaded with berberine (Beri) as the DFU-specific wound dressing. The wound healing efficacy of the fabricated dressings was evaluated in streptozotocin-induced diabetic rats. The results demonstrated an average nanofiber diameter of 502 ± 150 nm, and the tensile strength, contact angle, porosity, water vapor permeability and water uptake ratio of CA/Gel nanofibers were around 2.83 ± 0.08 MPa, 58.07 ± 2.35°, 78.17 ± 1.04%, 11.23 ± 1.05 mg/cm2/hr, and 12.78 ± 0.32%, respectively, while these values for CA/Gel/Beri nanofibers were 2.69 ± 0.05 MPa, 56.93 ± 1°, 76.17 ± 0.76%, 10.17 ± 0.21 mg/cm2/hr, and 14.37 ± 0.42%, respectively. The antibacterial evaluations demonstrated that the dressings exhibited potent antibacterial activity. The collagen density of 88.8 ± 6.7% and the angiogenesis score of 19.8 ± 3.8 obtained in the animal studies indicate a proper wound healing. These findings implied that the incorporation of berberine did not compromise the physical properties of dressing, while improving the biological activities. In conclusion, our results indicated that the prepared mat is a proper wound dressing for DFU management and treatment.

Model-Based Scale-Up Methodologies for Pharmaceutical Granulation

In the pharmaceutical industry, it is a major challenge to maintain consistent quality of drug products when the batch scale of a process is changed from a laboratory scale to a pilot or commercial scale. Generally, a pharmaceutical manufacturing process involves various unit operations, such as blending, granulation, milling, tableting and coating and the process parameters of a unit operation have significant effects on the quality of the drug product. Depending on the change in batch scale, various process parameters should be strategically controlled to ensure consistent quality attributes of a drug product. In particular, the granulation may be significantly influenced by scale variation as a result of changes in various process parameters and equipment geometry. In this study, model-based scale-up methodologies for pharmaceutical granulation are presented, along with data from various related reports. The first is an engineering-based modeling method that uses dimensionless numbers based on process similarity. The second is a process analytical technology-based modeling method that maintains the desired quality attributes through flexible adjustment of process parameters by monitoring the quality attributes of process products in real time. The third is a physics-based modeling method that involves a process simulation that understands and predicts drug quality through calculation of the behavior of the process using physics related to the process. The applications of these three scale-up methods are summarized according to granulation mechanisms, such as wet granulation and dry granulation. This review shows that these model-based scale-up methodologies provide a systematic process strategy that can ensure the quality of drug products in the pharmaceutical industry.

Effects of coupling agent on antioxidant properties and structure of PP/cotton stalk lignin composites

In this paper, the effects of coupling agent and lignin extracted from waste cotton stalks in Xinjiang on thermal-oxygen aging properties of polypropylene (PP) composites were studied. The melt index test and indoor thermal oxygen aging test was carried out on the samples treated with coupling agent. The mechanical properties, surface micromorphology, rheological properties and element composition of the materials before and after 30 days of aging were studied. The results showed that the titanate coupling agent was the best for improving the melt index and mechanical properties of PP/cotton stalk lignin composites. After the 30-day thermal oxygen aging test, the samples with 2% lignin had the best impact strength and retention rate of fracture elongation, reaching 68.9% and 77.3% respectively. The sample with 3% lignin content had the smoothen surface, no crack appeared. After aging, the increase of C=O was the least, and the crystal peak area decreased less.

Preparation of lignin containing cellulose nanofibers and its application in PVA nanocomposite films

Lignin containing cellulose nanofibers (LCNFs) were successfully prepared from wheat straw using an acid hydrotrope of p-toluene sulfonic acid (p-TsOH) combined with ultrasonication. p-TsOH pretreatment was applied below 80 °C to selectively remove hemicellulose and lignin and generate purified cellulose fibers containing approximately 15% lignin. Subsequently, high-intensity ultrasonication was used for <6 min to effectively defibrillate the p-TsOH-pretreated cellulose fibers to nanoscale fibers. AFM and TEM analyses showed that the diameter distribution of the resultant nanofibers decreased with the increase in ultrasonic intensity. The FTIR and XRD results indicated that the molecular structures and cellulose crystallinity were not changed during the ultrasonic process. An amount of 5 wt% of the obtained LCNFs was introduced into a polyvinyl alcohol (PVA) matrix. The resulting nanocomposite products exhibited improved thermal performance and surface properties compared with the pure PVA matrix. The mechanical properties, including the tensile stress and Young's modulus, were enhanced significantly, although the elongation at the break was slightly decreased. PVA composites with the addition of LCNFs are expected to be used in a variety of fields, such as biodegradable plastics, pharmaceutical carrier, filtration media and packaging materials.

Kraft lignin grafted with isopentenol polyoxyethylene ether and the dispersion performance

In order to develop a biomass-based superplasticizer, kraft lignin (KL) was grafted with isopentenol polyoxyethylene ether (TPEG) to prepare a novel macromonomer (KL-TPEG). It was shown that the retention ratio of the aliphatic CC bond increased from 81.07% to 90.20% with the increase of m(TPEG)/m(KL). When the grafting ratio was increased, the average number of TPEG grafted on one KL molecule was approximately 1.4, 3.1, 4.6, 6.2 and 7.6. The star-like structure was also confirmed by FT-IR, ¹H NMR and GPC. KL-TPEG had favorable surface activity and dispersion stability on the cement particles. It was illustrated that the shear stress and shear viscosity of the cement slurries with KL-TPEG were significantly less than that of blank slurry. The dispersion-retention ability of KL-TPEG on the slurry was also gradually enhanced with the increase of the grafting ratio of TPEG. It was seldom reported on the biomass-based TPEG. Through modified with KL, the rheology behavior and the dispersion-retention ability of TPEG was greatly improved, and the cost of TPEG was also reduced, thus this study not only promoted the development of biomass-based macromonomer, but also helped for the high value utilization of lignin.

Effect of lignin on the self-bonding of a natural fiber material in a hydrothermal environment: Lignin structure and characterization

Self-bonding natural fiber materials (SNFMs) were prepared at different initial moisture contents (IMCs) through a molding pressing process. The self-bonding mechanism of the SNFMs was deduced from the chemical and structural changes of lignin and their mechanical strengths. The structural transformations of milled wood lignin (MWL) in the SNFMs were investigated by two-dimensional heteronuclear single quantum coherence, quantitative 31P-nuclear magnetic resonance spectra, gelpermeation chromatography, and thermogravimetric analysis. As IMC increased from 0% to 80%, the tensile strength increased from 23.0 to 70.0 MPa and the density increased from 0.99 to 1.05 g/cm3. IMC affected the distribution and abundance of the typical lignin linkages (β-O-4', β-β, and β-5') and the S-OH/G-OH ratios of lignin. Moreover, as IMC increased, the aliphatic hydroxyl groups proportionally decreased, while the condensed phenolic and non-condensed phenolic hydroxyl groups increased, the molecular weight of MWL became larger, and the thermal stability of lignin improved. These findings indicate the simultaneous occurrence of depolymerization and condensation reactions of lignin. The condensation reaction dominated, improving the mechanical strength of the material. Our results explain (at least partly) the self-bonding mechanism of SNFMs.

Graft modification of lignin-based cellulose via enzyme-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization and free-radical coupling

In this study, a green approach combining enzyme-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization and free-radical coupling was developed for the modification of jute fiber, which is a typical lignin-based cellulose. Jute fiber surface was covered by rich amount of lignin, which offered great opportunities for further functional modification. The controlled polymerization of vinyl monomers, acrylamide (AM) or butyl acrylate (BA), was carried out by horseradish peroxidase (HRP)-initiated RAFT to form well-defined polymers with well-controlled molecular weights and structures. Enzymatic grafting by HRP occurred between the free radicals of well-defined polymers and free radicals of lignin on jute. Gel permeation chromatography (GPC) analysis indicated the alkyl chain length of polymers prepared via HRP-initiated RAFT polymerization was well-controlled. Other results of flourier transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) revealed that well-controlled alkyl chains prepared via enzymatic catalysis were grafted on the exposed lignin of jute. The study explores a new and eco-friendly modification method for lignin-based materials with the controlled graft chain structure via two different catalysis with HRP.

Using a Material Library to Understand the Impacts of Raw Material Properties on Ribbon Quality in Roll Compaction

The purpose of this study is to use a material library to investigate the effect of raw material properties on ribbon tensile strength (TS) and solid fraction (SF) in the roll compaction (RC) process. A total of 81 pharmaceutical materials, including 53 excipients and 28 natural product powders (NPPs), were characterized by 22 material descriptors and were compacted under five different hydraulic pressures. The transversal and longitudinal splitting behaviors of the ribbons were summarized. The TS-porosity and TS-pressure relationships were used to explain the roll compaction behavior of powdered materials. Through defining the target ribbon quality (i.e., 0.6 ≤ SF ≤ 0.8 and TS ≥ 1 MPa), the roll compaction behavior classification system (RCBCS) was built and 81 materials were classified into three categories. A total of 24 excipients and five NPPs were classified as Category I materials, which fulfilled the target ribbon quality and had less occurrence of transversal splitting. Moreover, the multivariate relationships between raw material descriptors, the hydraulic pressure and ribbon quality attributes were obtained by PLS regression. Four density-related material descriptors and the cohesion index were identified as critical material attributes (CMAs). The multi-objective design space summarizing the feasible material properties and operational region for the RC process were visualized. The RCBCS presented in this paper enables a formulator to perform the initial risk assessment of any new materials, and the data modeling method helps to predict the impact of formulation ingredients on strength and porosity of compacts.

A rapid and quantitative method for assessing the whiteness of whitened lignin based on an in-depth analysis of reported methods

The modification of lignin to a lighter color has been a concern in lignin valorization. In the previous reports on lignin color reduction, the methods of assessing the whiteness of lignin varied from each other, due to the absence of a universal method for characterizing the lightness/darkness of dark samples. In this paper, the reported methods for assessing the whiteness of lignin were analyzed, including "comparison of absorbance curve", "absorbance at specific wavelength", "ISO or TAPPI brightness" and "photograph observation". Our study revealed that various defects existed in these methods. In light of the Munsell color system, we herein proposed a quantitative method for evaluating the whiteness of lignin, based on the finding that the sum of the reflectance of samples with the same Munsell value (whiteness) are substantially equal. A model for converting the reflectance of lignin to Munsell value was established, and the effectiveness of the model was verified and discussed. The standard deviation of the model ranges from 0.23-1.10. The applicability of the method to liquid was also discussed in the paper. Moreover, because the model was derived from the Munsell color system, it can also be applied to characterize other medium to dark-colored objects besides lignin.

Formulation of Direct Compression Zidovudine Tablets to Correlate the SeDeM Diagram Expert System and the Rotary Press Simulator Styl'ONE Results

The SeDeM diagram expert system has been applied to study Zidovudine and some excipients. From the obtained diagrams, a pharmaceutical formula has been designed. SeDeM diagram ascertains the critical parameters that are suitable for a direct compression. The formula is compressed using a rotary tablet press simulator which emulates rotary tablet press' compression profiles. From these compressions, we study the formula behavior under different industrial production conditions but saving a huge amount of material. The study is done at different compression forces and compression speeds and taking into account the influence of the pre-compression force. The differences observed between the compression profiles are hereby described. The results indicate that the formulation is able to be compressed adequately with the emulated compression profiles and no differences are observed between the final products. Therefore, we can assure that the SeDeM diagram expert system is accurate and robust. Moreover, its results are comparable with the compression results in a rotary tablet press, which has never been described in the pharmaceutical literature before. From the obtained results, it is possible to select the best rotary press to scale-up this formulation.

Functionalization of wool fabric using lignin biomolecules extracted from groundnut shells

Food and agro-processing industries generate a huge quantity of solid waste which is rich in bio-macromolecules like lignin. The extraction of lignin biomolecules can help in the efficient management of such waste along with the generation of wealth from the waste. The groundnut shells are one of the lignin-rich wastes which could be utilized for the extraction of lignin biomolecules. The present work investigates an innovative approach involving the application of extracted lignin biomolecules for the value-addition to wool fabrics. Metallic mordants were utilized to get a wash-fast attachment of lignin with wool. The change in the appearance of wool fabrics was analyzed using reflectance spectroscopy. The finished fabrics were further evaluated for the functional properties like antioxidant activity, antibacterial activity and UV protection. The functionalized wool fabrics displayed a variety of shades with different combinations of groundnut shell lignin (GSL) and mordant. Thermal stability of treated wool fabrics was analyzed by thermogravimetric analysis. The functionalized wool fabrics showed significant antioxidant activity (69.5-84.5%), antibacterial activity (79.7-86.3%) and UV protection (UPF ratings of 50⁺).

Highly efficient and stable catalysis of p-nitrophenol via silver/lignin/polyacrylic acid hydrogel

As the second largest natural polymer in nature, lignin has a large amount of reserves and has important practical application value, which has attracted increasing attention. Ag@LPAH, a nanometer silver catalyst with a 3D structure, was successfully prepared in a simple operation. In batch experiment and fixed-bed experiment, it showed excellent catalytic degradation ability and stability of 4-NP. Thanks to the large number of carboxyl groups present in the lignin-polyacrylic acid hydrogel, the silver nanoparticles are well controlled to grow with no agglomeration. Ag@LPAH-20 exhibited optimal catalytic performance and stability, requiring only 123 s to complete the reaction and maintaining 99% catalytic efficiency after 10 cycles. In addition, the catalytic efficiency can be maintained over 90% for more than 120 min in fixed bed experiment.

Microcrystalline cellulose from Posidonia oceanica brown algae: Extraction and characterization

Posidonia oceanica brown algae (POBA) represent an abundant and renewable biomass in Algerian seas. In the present study, the POBA were chemically treated through delignification and alkali treatment followed by acid hydrolysis to produce pure microcrystalline cellulose (MCC). FTIR analysis indicates that most lignin and hemicellulose were eliminated during the chemical treatments. The XRD measurements revealed that the obtained cellulose and MCC belong to cellulose I polymorph, with crystallinity index of 60.50% and 74.23%, respectively. SEM micrographs of the produced MCC showed a non-uniform micro sized rod-like shape morphology with an average diameter of 8.4 ± 2.1 μm. The thermal analysis results exhibited that the decomposition temperature of the prepared MCC shifted to higher temperature compared to that of the respective cellulose and raw POBA. The authenticity of the prepared MCC was also examined by comparing its physicochemical properties with those of commercial MCC. Based on these analyses, POBA-MCC showed tremendous potential to be used in several applications.

Potential of di-aldehyde cellulose for sustained release of oxytetracycline: A pharmacokinetic study

This study focused on the in-vivo sustained release of oxytetracycline (OTC) loaded on di-aldehyde cellulose (DAC). The periodate oxidation method was used for the synthesis of DAC. The prepared DAC-OTC material was characterized by different techniques such as Scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and particle size analyzer. The pharmacokinetic studies were performed on DAC-OTC composite system and commercial tablet (COTA). The results of pharmacokinetic studies demonstrated that DAC-OTC exhibited higher area under the curve (AUC) (482.8 μghmL^-1) as compared to COTA (90.72 μghmL^-1). DAC-OTC composite system has double compartment pattern with improvement in mean residing time (MRT) and area under moment curve (AUMC_0-∞) than the commercial tablet (2.8 and 15.13 folds higher, respectively). Swelling index of DAC-OTC at different pH and pKa of OTC release imply that controlled in-vivo release in DAC-OTC composite system could be due to the simultaneous occurrence of the covalent and hydrogen bond between OTC and di-aldehyde cellulose. These results indicate that di-aldehyde cellulose may improve the in-vivo bioavailability of OTC.