Synthesis of folate mediated carboxymethyl cellulose fatty acid ester and application in drug controlled release

Sandwich hydrogel to realize cartilage-mimetic structures and performances from polyvinyl alcohol, chitosan and sodium hyaluronate

Developing artificial substitutes that mimic the structures and performances of natural cartilage is of great importance. However, it is challenging to integrate the high strength, excellent biocompatibility, low coefficient of friction, long-term wear resistance, outstanding swelling resistance, and osseointegration potential into one material. Herein, a sandwich hydrogel with cartilage-mimetic structures and performances was prepared to achieve this goal. The precursor hydrogel was obtained by freezing-thawing the mixture of poly vinyl alcohol, chitosan and deionized water three cycles, accompanied by soaking in sodium hyaluronate solution. The top of the precursor hydrogel was hydrophobically modified with lauroyl chloride and then loaded with lecithin, while the bottom was mineralized with hydroxyapatite. Due to the multiple linkages (crystalline domains, hydrogen bonds, and ionic interactions), the compressive stress was 71 MPa. Owing to the synergy of the hydrophobic modification and lecithin, the coefficient of friction was 0.01. Additionally, no wear trace was observed after 50,000 wear cycles. Remarkably, hydroxyapatite enabled the hydrogel osseointegration potential. The swelling ratio of the hydrogel was 0.06 g/g after soaking in simulated synovial fluid for 7 days. Since raw materials were non-toxic, the cell viability was 100 %. All of the above merits make it an ideal material for cartilage replacement.

Surface-anchored microbial enzyme-responsive solid lipid nanoparticles enabling colonic budesonide release for ulcerative colitis treatment

Colon-targeted oral drug delivery systems (CDDSs) are desirable for the treatment of ulcerative colitis (UC), which is a disease with high relapse and remission rates associated with immune system inflammation and dysregulation localized within the lining of the large bowel. However, the success of current available approaches used for colon-targeted therapy is limited. Budesonide (BUD) is a corticosteroid drug, and its rectal and oral formulations are used to treat UC, but the inconvenience of rectal administration and the systemic toxicity of oral administration restrict its long-term use. In this study, we designed and prepared colon-targeted solid lipid nanoparticles (SLNs) encapsulating BUD to treat UC by oral administration. A negatively charged surfactant (NaCS-C12) was synthesized to anchor cellulase-responsive layers consisting of polyelectrolyte complexes (PECs) formed by negatively charged NaCS and cationic chitosan onto the SLNs. The release rate and colon-specific release behavior of BUD could be easily modified by regulating the number of coated layers. We found that the two-layer BUD-loaded SLNs (SLN-BUD-2L) with a nanoscale particle size and negative zeta potential showed the designed colon-specific drug release profile in response to localized high cellulase activity. In addition, SLN-BUD-2L exhibited excellent anti-inflammatory activity in a dextran sulfate sodium (DSS)-induced colitis mouse model, suggesting its potential anti-UC applications.

Host-guest drug delivery by β-cyclodextrin assisted polysaccharide vehicles: A review

Among different form of cyclodextrin (CD), β-CD has been taken a special attraction in pharmaceutical science due to lowest aqueous solubility and adequate cavity size. When β-CD forms inclusion complex with drugs then biopolymers such as polysaccharides in combination plays a vital role as a vehicle for safe release of drugs. It is noticed that, β-CD assisted polysaccharide-based composite achieves better drug release rate through host-guest mechanism. Present review is a critical analysis of this host-guest mechanism for release of drugs from polysaccharide supported β-CD inclusion complex. Various important polysaccharides such as cellulose, alginate, chitosan, dextran, etc. in relevant to drug delivery are logically compared in present review by their association with β-CD. Efficacy of mechanism of drug delivery by different polysaccharides with β-CD is analytically examined in schematic form. Drug release capacity at different pH conditions, mode of drug release, along with characterization techniques adopted by individual polysaccharide-based CD complexes are comparatively established in tabular form. This review may explore better visibility for researchers those are working in the area of controlled release of drugs by vehicle consist of β-CD associated polysaccharide composite through host-guest mechanism.

An investigation on the adsorption and removal performance of a carboxymethylcellulose-based 4-aminophenazone@MWCNT nanocomposite against crystal violet and brilliant green dyes

The multistep chemical modification of carboxymethylcellulose (CMC) in the presence of 4-aminophenazone (A-PH) and multiwall carbon nanotubes (MWCNTs) has been successfully conducted. The environmental performance of this material has been thoroughly investigated. Crystal violet (CV) and brilliant green (BG) were eliminated by utilising a new hybrid nanocomposite material (A-PH-CMC/MWCNTs) from a simulated textile wastewater solution. Using SEM, EDX, XRD and FTIR spectroscopy methods, the detailed characterisation of A-PH-CMC/MWCNT nanocomposites was investigated. The results indicated that the adsorption capacity was dependent on six factors (e.g., contact duration, starting concentration, adsorbent mass, the effect of the solution pH, temperature and the effect of KNO₃). In addition, thermodynamic and regeneration studies have been reported. According to the theories of pseudo-second-order kinetics, the removal process involves chemical adsorption. The experimental results were best suited by the Langmuir model, in which maximum adsorption capacities of 20.83 and 22.42 mg g^-1 were predicted for the BG and CV dyes, respectively. The research is a preliminary case study demonstrating the excellent potential of A-PH-CMC/MWCNT nanocomposites as a material for CV and BG dye removal.

Wood-Derived Functional Polymeric Materials

In recent years, tremendous efforts have been dedicated to developing wood-derived functional polymeric materials due to their distinctive properties, including environmental friendliness, renewability, and biodegradability. Thus, the uniqueness of the main components in wood (cellulose and lignin) has attracted enormous interest for both fundamental research and practical applications. Herein, the emerging field of wood-derived functional polymeric materials fabricated by means of macromolecular engineering is reviewed, covering the basic structures and properties of the main components, the design principle to utilize these main components, and the resulting wood-derived functional polymeric materials in terms of elastomers, hydrogels, aerogels, and nanoparticles. In detail, the natural features of wood components and their significant roles in the fabrication of materials are emphasized. Furthermore, the utilization of controlled/living polymerization, click chemistry, dynamic bonds chemistry, etc., for the modification is specifically discussed from the perspective of molecular design, together with their sequential assembly into different morphologies. The functionalities of wood-derived polymeric materials are mainly focused on self-healing and shape-memory abilities, adsorption, conduction, etc. Finally, the main challenges of wood-derived functional polymeric materials fabricated by macromolecular engineering are presented, as well as the potential solutions or directions to develop green and scalable wood-derived functional polymeric materials.