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Drugs and Therapeutics
Published in James Sherifi, General Practice Under the NHS, 2023
Sodium alginate was originally extracted from seaweed. Along with simple antacids, such as magnesium trisilicate, it was the mainstay of managing dyspepsia before the introduction of more targeted drugs. Gaviscon was aggressively marketed for heartburn, gastro-oesophageal reflux, with dubious claims of a dual action in acid suppression and coating the lower oesophagus, thus preventing mucosal irritation.
Marine Polysaccharides from Algae
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Wen-Yu Lu, Hui-Jing Li, Yan-Chao Wu
Propylene glycol sodium alginate sodium sulfate (PSS), a sulfated polysaccharide derivative of alginate, was isolated from Marine brown algae. PSS is an oral heparin-like drug. It is the first drug approved by China food and Drug Administration (CFDA) in 1987 for the treatment of hyperlipidemia and ischemic cardiovascular and cerebrovascular diseases (Wu et al., 2016). The basic carbohydrate chain of PSS is composed of 1→4 linked β-D-mannituronic acid (M) and α-L-guluronic acid (G), including the homooligomeric regions of M-blocks, G-blocks, and MG-blocks (Figure 4.6). In general, the relative molecular weight (Mw) of PSS is 10–20 kDa and the organic sulfur content is 9.0–14.0%. PSS could be obtained by hydrolysis, esterification and sulfation of sodium alginate. The biological activity of PSS is related to its Mw, uronic acid composition (M/G ratio) and degree of sulfate substitution (DS) (Xue et al., 2018).
Production, Extraction and Characterization of Alginates from Seaweeds
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
Faiez Hentati, Alina V. Ursu, Guillaume Pierre, Cedric Delattre, Bogdan Trica, Slim Abdelkafi, Gholamreza Djelveh, Tanase Dobre, Philippe Michaud
At the concentrations used in industrial applications, alginates are non-Newtonian pseudoplastic fluids since the viscosity decreases as the rate of shear increases (McHugh 1987). The addition of NaCl to sodium alginate solutions induced a significant increase of alginate solutions viscosity as Na+ ions favor inter-chain associations (Draget et al. 2006). This effect becomes more pronounced when the G content increases (Ma et al. 2014). Seale (1982) proposed three modes of binding of univalent cations in addition to general polyelectrolyte effects: weak chelation by M and isolated G residues, specific site-binding to adjacent G and cooperative “egg-box” binding. The viscosifying properties depend on the molecular conformation of the polymer and can be influenced by the ionic strength of the solvent. This sensitivity of viscosity to ionic strength is typical of polyelectrolytes which normally exhibit high viscosities at low ionic strength (due to an expanded chain conformation caused by charge-charge repulsions) and lower viscosities at higher ionic strength (due to a more compacted conformation) (Lapasin and Pricl 1995). The viscosity of an alginate solution will significantly decrease with the temperature increasing (McHugh 1987). Ma et al. (2014) published the temperature-dependent behavior of sodium alginate solution and a good correlation to the Arrhenius model. Low concentration of Ca2+ in an alginate solution resulted, for example, in an increase of its viscosity due to the formation of inter-chain interactions (McHugh 1987).
Green polymer altered in-situ gel oral liquid sustainable release preparation of vildagliptin suitable for dysphagic diabetic patients: assessment in-vitro & in-vivo
Published in Pharmaceutical Development and Technology, 2023
Soha M. El-masry, Heba M. ElBedaiwy, Mohammad M. Abd-Alhaseeb, Mohamed S. Abdel-Maksoud, Doaa A. Habib
These findings demonstrate the beneficial synergistic effect between sodium alginate and CMC. The gelation of alginate carboxymethylcellulose in-situ gel matrix could be attributed to the passive diffusion of ions from the gastric fluid into the in-situ gel matrix, where, the carboxylic groups of sodium alginate are ionically crosslinked with Ca2+, meanwhile CMC and CaCl2 form an aggregate with each other (Riyajan and Nuim 2013). This was revealed from Calculated release efficiency values, which showed a significant decrease (P ˂0.05) in the vildagliptin release efficiency from formulations containing CMC (F3, F4, and F5) compared to the CMC free system (F2) with significant differences (P ˂ 0.05) between formulations containing different CMC concentrations of 0.1, 0.2, and 0.3 mg. (Table 2). Additionally, this can be explained based on the blending of sodium alginate (1.5% w/w) with CMC, which results in decreasing the dissolution of sodium alginate in water, due to the formation of Hydrogen bonds between SA and CMC resulting in a decrease in its solubility (Pourjavadi et al. 2006). The hydrogen interaction between the hydroxyl group from vildagliptin and the carboxylic group of SA and CMC results in controlling the release of vildagliptin from the fabricated in-situ gel matrix.
Alginate-based matrix tablets for drug delivery
Published in Expert Opinion on Drug Delivery, 2023
Natalia Veronica, Paul Wan Sia Heng, Celine Valeria Liew
As a pH sensitive polymer, alginate’s solubility and hydration characteristics depend on the pH of the dissolution environment. Chan et al. [42] investigated the swelling behavior of sodium alginate tablets. The influence of dissolution medium pH and alginate grades was also evaluated. The study observed that hydrated alginate-based matrix tablets exhibited anisotropic matrix swelling with preferential swelling in the axial direction. Regarding pH of the dissolution medium and viscosity of the sodium alginate, the study found that in the acidic pH, compacts produced from a lower viscosity grade of sodium alginate (Manucol LB, 3 cps at 1%, w/w) exhibited a greater extent of swelling in the axial direction compared to the compacts produced from a higher viscosity grade of alginate (Manucol SS/LL, 108 cps at 1%, w/w). Both grades of sodium alginate had similar extent of radial expansion in the acidic phase. In neutral pH, the higher viscosity grade sodium alginate matrix had enhanced expansion in both axial and radial directions, whereas the lower viscosity grade showed a slower increase in the axial direction with a minimal change in the radial direction. This translates to a marginal influence of alginate viscosity on the drug release in acidic pH, and that the viscosity has a greater effect on the drug release in neutral pH.
Silver nanoparticles obtained from Brazilian pepper extracts with synergistic anti-microbial effect: production, characterization, hydrogel formulation, cell viability, and in vitro efficacy
Published in Pharmaceutical Development and Technology, 2021
Daniele M. de Oliveira, Diego B. Menezes, Lucas R. Andrade, Felipe da C. Lima, Luciana Hollanda, Aleksandra Zielinska, Elena Sanchez-Lopez, Eliana B. Souto, Patrícia Severino
In this work, the production of silver nanoparticles (AgNPs) has been described, applying a green methodology using the hydroalcoholic extract of leaves of Brazilian pepper S. terebinthifolius Raddi as a reducing agent of the metal. AgNPs were physicochemically characterized and formulated in sodium alginate/gelatin hydrogels. The developed formulations demonstrated anti-bacterial activity against selected Gram-positive and Gram-negative strains, and without significant cytotoxicity against fibroblasts cell lines. Plant species have outstanding biological activities, including against several microorganisms; besides, they can be used for green synthesis as a precursor route of metallic nanoparticles, as silver nanoparticles. Sodium alginate, the base polymer of the topical formulation, has also been shown to have antibacterial activity; a synergistic effect can be exploited for further use in the treatment of skin infections.