Control and Preparation of Quaternized Chitosan and Carboxymethyl Chitosan Nanoscale Polyelectrolyte Complexes Based on Reactive Flash Nanoprecipitation

Combination of self-assembling system and N,O-carboxymethyl chitosan improves ocular residence of anti-glaucoma drug

Glaucoma is known to be one of the principal causes of vision loss due to elevated intraocular pressure. Currently, latanoprost eye drops is used as first-line treatment for glaucoma; however, it possesses low bioavailability due to rapid precorneal clearance. A novel delivery system with a mucoadhesive property could overcome this problem. Therefore, we attempt to develop a combination of self-assembling latanoprost nanomicelles (Latcel) and a mucoadhesive polymer (N,O-carboxymethyl chitosan: N,O-CMC) to improve the corneal residence time. Latcel was developed using Poloxamer-407 by thin film hydration method, followed by the addition of N,O-CMC using simple solvation to obtain Latcel-CMC and characterized using various physicochemical characterization techniques. The particle size of Latcel-CMC was 94.07 ± 2.48 nm and a zeta potential of -16.03 ± 0.66 mV, with a sustained release for 24h whereas marketed latanoprost drops released 90 % of the drug within 1h. In vitro cytotoxicity studies, HET-CAM, and in vivo Draize test showed the biocompatibility of Latcel-CMC. Cellular uptake studies performed using fluorescein isothiocyanate (FITC) loaded nanomicelles in human corneal epithelial cells indicates the increased cellular uptake as compare to plain FITC solution. In vivo ocular residence time was evaluated in Wistar rats using Indocyanine green (ICG) loaded nanomicelles by an in vivo imaging system (IVIS), indicating Latcel-CMC (8h) has better residence time than plain ICG solution (2h). The Latcel-CMC showed improved corneal residence time and sustained release of latanoprost due to increased mucoadhesion. Thus, the developed N,O-Carboxymethyl chitosan based nanomicelles eye drop could be a better strategy than conventional eye drops for topical delivery of latanoprost to treat glaucoma.

Flash nanoprecipitation allows easy fabrication of pH-responsive acetalated dextran nanoparticles for intracellular release of payloads

Acetalated dextran (Ac-Dex) nanoparticles are currently of immense interest due to their sharp pH-responsive nature and high biodegradability. Ac-Dex nanoparticles are often formulated through single- or double-emulsion methods utilizing polyvinyl alcohol as the stabilizer. The emulsion methods utilize toxic organic solvents such as dichloromethane or chloroform and require multi-step processing to form stable Ac-Dex nanoparticles. Here, we introduce a simple flash nanoprecipitation (FNP) approach that utilizes a confined impinging jet mixer and a non-toxic solvent, ethanol, to form Ac-Dex nanoparticles rapidly. Ac-Dex nanoparticles were stabilized using nonionic PEGylated surfactants, D-α-Tocopherol polyethylene glycol succinate (TPGS), or Pluronic (F-127). Ac-Dex nanoparticles formed using FNP were highly monodisperse and stably encapsulated a wide range of payloads, including hydrophobic, hydrophilic, and macromolecules. When lyophilized, Ac-Dex TPGS nanoparticles remained stable for at least one year with greater than 80% payload retention. Ac-Dex nanoparticles were non-toxic to cells and achieved intracellular release of payloads into the cytoplasm. In vivo studies demonstrated a predominant biodistribution of Ac-Dex TPGS nanoparticles in the liver, lungs, and spleen after intravenous administration. Taken together, the FNP technique allows easy fabrication and loading of Ac-Dex nanoparticles that can precisely release payloads into intracellular environments for diverse therapeutic applications. pH-responsive Acetalateddextran can be formulated using nonionic surfactants, such as TPGS or F-127, for intracellular release of payloads. Highly monodisperse and stable nanoparticles can be created through the simple, scalable flash nanoprecipitation technique, which utilizes a confined impingement jet mixer.

Chitosan nanoparticles and based composites as a biocompatible vehicle for drug delivery: A review

The shellfish processing industry is one of the largest growing industries across the globe with a market size of around USD 62B. However, it also leads to a significant environmental issue as it produces >80,000 tons of waste shells globally. Unfortunately, the slow degradation of this waste causes it to accumulate over time, posing a serious threat to the marine environment. The key solution to this problem is to recycle this sea waste into a valuable product like chitin which is further used to produce chitosan. Chitosan is a natural biopolymeric substance obtained via N-deacetylation of the chitin. The chitosan-based nanoparticles are further useful for the fabrication of biopolymeric nanocomposites which are used in various biomedical applications specifically in drug delivery. Here, we review the recent advancements in the development of chitosan-based nanocomposites as a biocompatible carrier for drug delivery, specifically focusing on gene delivery, wound healing, microbial treatment, and anticancer drug delivery. By providing a valuable and up-to-date resource, this review illuminates the current state of research concerning chitosan's pivotal role in the biomedical domain as an efficacious drug delivery agent.

The mechanism, biopolymers and active compounds for the production of nanoparticles by anti-solvent precipitation: A review

The anti-solvent precipitation method has been investigated to produce biopolymeric nanoparticles in recent years. Biopolymeric nanoparticles have better water solubility and stability when compared with unmodified biopolymers. This review article focuses on the analysis of the state of the art available in the last ten years about the production mechanism and biopolymer type, as well as the used of these nanomaterials to encapsulate biological compounds, and the potential applications of biopolymeric nanoparticles in food sector. The revised literature revealed the importance to understand the anti-solvent precipitation mechanism since biopolymer and solvent types, as well as anti-solvent and surfactants used, can alter the biopolymeric nanoparticles properties. In general, these nanoparticles have been produced using polysaccharides and proteins as biopolymers, especially starch, chitosan and zein. Finally, it was identified that those biopolymers produced by anti-solvent precipitation were used to stabilize essential oils, plant extracts, pigments, and nutraceutical compounds, promoting their application in functional foods.

Synthesis and characterization of thiazolium chitosan derivative with enhanced antimicrobial properties and its use as component of chitosan based films

In this work, chemical modification of chitosan using cationic thiazolium groups was investigated with the aim to improve water solubility and antimicrobial properties of chitosan. Enzymatic synthesis and ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) chemistry were employed to synthesize and attach to chitosan through the amine groups the molecule bearing thiazolium moieties, quaternized 4-(2-(4-methylthiazol-5-yl) ethoxy)-4-oxobutanoic acid (MTBAQ). On the basis of Fourier transform infrared spectroscopy (FTIR), elemental analysis and solid state nuclear magnetic resonance (ssNMR), around 95 % of the available amine groups of chitosan (of 25 % degree of acetylation) reacted. The resulting derivative was water soluble at physiological pH and exhibit excellent antimicrobial activity against Listeria innocua, Staphylococcus epidermidis, Staphylococcus aureus and Methicillin Resistant S. aureus Gram-positive bacteria (MIC = 8-32 μg/ mL), whereas its efficiency decreases against fungi Candida albicans and Eschericia coli Gram-negative bacterium. Subsequently, the thiazolium chitosan derivative was employed as antimicrobial component (up to 7 wt%) of chitosan/glycerol based films. The incorporation of the chitosan derivative does not modify significantly the characteristics of the film in terms of thermal and mechanical properties, while enhances considerably the antimicrobial activity.

Chitosan - dextran phosphate carbamate hydrogels for locally controlled co-delivery of doxorubicin and indomethacin: From computation study to in vivo pharmacokinetics

The development of synergistic drug combinations is a promising strategy for effective cancer suppression. Here, we report all-polysaccharide biodegradable polyelectrolyte complex hydrogels (DPCS) based on dextran phosphate carbamate (DP) and chitosan (CS) for controlled co-delivery of the anticancer drug doxorubicin (DOX) and the non-steroidal anti-inflammatory drug indomethacin (IND). IND can induce more apoptosis in tumor cells by reducing the level of multidrug resistance-associated protein 1. Based on calculations using density functional theory and zeta potential analysis data, carriers with high drug loading were obtained. The release profile of both drugs from the hydrogels was tuned by changing the molecular weight and functional groups content of the polysaccharides. The optimized DPCS showed a steady release of DOX both in vitro and in vivo, and a gradual release of IND, which constantly induced the action of DOX. Considering all of these benefits, DOX- and IND-loaded DPCS offer a promising long-acting polysaccharide-based antitumor platform.