Determination of molecular-weight distribution of chitosan by high-performance liquid chromatography

Physicochemical and Colligative Investigation of α (Shrimp Shell)- and β (Squid Pen)-Chitosan Membranes: Concentration-Gradient-Driven Water Flux and Ion Transport for Salinity Gradient Power and Separation Process Operations

Chitin, and its derivative chitosan, is a naturally occurring biopolymer and an abundant polysaccharide containing acetylated units of N-acetyl-d-glucosamine. Chitosan membranes produced from shrimp shell (α) and squid pen (β) biowaste were prepared by solvent-casting, after which water flux and ionic transport diffusion experiments were conducted using a side-by-side concentration test cell under differing salinity concentration gradients. Physicochemical and experimental investigations were conducted, which confirmed that β-chitin possesses differing and enhanced performance characteristics than α-chitin with respect to diffusive water flux and ionic transport capabilities. In addition, novel colligative investigations through osmotic equilibrium were conducted to determine electrochemical characteristics for the evaluation of salinity gradient power generation suitability. Electrochemical test results under a salinity gradient revealed extremely low energy density values, thereby limiting consideration for commercial utility-scale salinity gradient power renewable energy operations. However, the tested membranes possessed high water and ion flux permeability characteristics that could find use in industrial separation process operations such as those used in the extraction of economically valuable materials from seawater or highly saline industrial fluids, or reduction in the saline content of mining fluids during dewatering and hazardous waste treatment and disposal operations, thereby potentially fostering new market developments, which will drive continued improvements in the responsible biowaste management of this valuable marine bioresource.

Skin protectant textiles loaded with fish collagen, chitosan and oak galls extract composite

Skin protection and control of its microbial pathogens are highly important demands; natural biological agents are the ideals for that. Collagen (Cg) was extracted and characterized from skin and scales of Nile tilapia fish (Oreochromis niloticus), chitosan (Cts) was extracted from shrimp shells and extract of oak (Quercus infectoria) galls (OGE) was prepared. The antimicrobial potentialities of extracted agents, Cts and OGE, were qualitatively proved against skin pathogens, Staphylococcus aureus and Candida albicans, including both antibiotic sensitive and resistant strains, neither Cg nor negative control exhibited antimicrobial actions toward examined strain. The entire agents were loaded onto cotton fabrics and evaluated for antimicrobial actions and durability. Loaded textiles with the combined extracts' composite were the most effectual followed by individual treatments with OGE and Cts, respectively. Treated textiles upheld most of their antimicrobial activity after 2 laundering cycles toward all microbial pathogens. This invention could be consequently applied for production of skin protectant and hygienic fabrics.

Microencapsulation of probiotics for gastrointestinal delivery

The administration of probiotic bacteria as nutraceuticals is an area that has rapidly expanded in recent years, with a global market worth $32.6 billion predicted by 2014. Many of the health promoting claims attributed to these bacteria are dependent on the cells being both viable and sufficiently numerous in the intestinal tract. The oral administration of most bacteria results in a large loss of viability associated with passage through the stomach, which is attributed to the high acid and bile salt concentrations present. This loss of viability effectively lowers the efficacy of the administered supplement. The formulation of these probiotics into microcapsules is an emerging method to reduce cell death during GI passage, as well as an opportunity to control release of these cells across the intestinal tract. The majority of this technology is based on the immobilization of bacteria into a polymer matrix, which retains its structure in the stomach before degrading and dissolving in the intestine, unlike the diffusion based unloading of most controlled release devices for small molecules. This review shall provide an overview of progress in this field as well as draw attention to areas where studies have fallen short. This will be followed by a discussion of emerging trends in the field, highlighting key areas in which further research is necessary.

Polymeric Enhancers of Mucosal Epithelia Permeability: Synthesis, Transepithelial Penetration-Enhancing Properties, Mechanism of Action, Safety Issues

Transmucosal drug administration across nasal, buccal, and ocular mucosae is noninvasive, eliminates hepatic first-pass metabolism and harsh environmental conditions, allows rapid onset, and further, mucosal surfaces are readily accessible. Generally, however, hydrophilic drugs, such as peptides and proteins, are poorly permeable across the epithelium, which results in insufficient bioavailability. Therefore, reversible modifications of epithelial barrier structure by permeation enhancers are required. Low molecular weight enhancers generally have physicochemical characteristics favoring their own absorption, whereas polymeric enhancers are not absorbed, and this minimizes the risk of systemic toxicity. The above considerations have warranted the present survey of the studies on polymeric transmucosal penetration-enhancers that have appeared in the literature during the last decade. Studies on intestinal permeation enhancers are also reviewed as they give information on the mechanism of action and safety of polymers. The synthesis and characterization of polymers, their effectiveness in enhancing the absorption of different drugs across different epithelium types, their mechanism of action and structure-efficacy relationship, and the relevant safety issues are reviewed. The active polymers are classified into: polycations (chitosan and its quaternary ammonium derivatives, poly-L-arginine (poly-L-Arg), aminated gelatin), polyanions (N-carboxymethyl chitosan, poly(acrylic acid)), and thiolated polymers (carboxymethyl cellulose-cysteine, polycarbophil (PCP)-cysteine, chitosan-thiobutylamidine, chitosan-thioglycolic acid, chitosan-glutathione conjugates).

A comparison of glycans and polyglycans using solid-state NMR and X-ray powder diffraction

Individual polyglycans and their corresponding monomers have been studied separately for several decades. Attention has focused primarily on the modifications of these polyglycans instead of the simple relationship between the polyglycans themselves and their corresponding monomers. Two polyglycans, chitin and chitosan, were examined along with their respective monomeric units, N-acetyl-D-glucosamine (GlcNAc) and (+)D-glucosamine (GlcN) using solid-state proton decoupling Magic Angle Turning (MAT) techniques and X-Ray Powder Diffraction (XRPD). A down-field shift in isotropic (13)C chemical shifts was observed for both polymers in Cross Polarization/Magic Angle Spinning (CP/MAS) spectra. An explanation of misleading peak assignments in previous NMR studies for these polyglycans was determined by comparing sideband patterns of the polymers with their corresponding monomers generated in a 2D FIve pi REplicated Magic Angle Turning (FIREMAT) experiment processed by Technique for Importing Greater Evolution Resolution (TIGER). Structural changes in the crystalline framework were supported by XRPD diffraction data.

Chitosan: a unique polysaccharide for drug delivery

The aim of this review is to give an insight into the many potential applications of chitosan as a pharmaceutical drug carrier. The first part of this review concerns the principal uses of chitosan as an excipient in oral formulations (particularly as a direct tableting agent) and as a vehicle for parenteral drug delivery devices. The use of chitosan to manufacture sustained-release systems deliverable by other routes (nasal, ophthalmic, transdermal, and implantable devices) is discussed in the second part.