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Pullulan: Properties and Applications
Published in Shakeel Ahmed, Aisverya Soundararajan, Pullulan, 2020
Showkat Ali Ganie, Tariq Ahmad Mir, Akbar Ali, Qing Li
Pullulan is currently widely examined for different applications in the biomedical field. This is, for the most part, because of its noncarcinogenic, nontoxic, nonimmunogenic, nonmutagenic, and biodegradable properties. In contrast to a comparative yet progressively well-known polysaccharide, dextran, the rate of degradation of pullulan in serum is quicker than that of dextran. After the incubation period of 48 h, 0.7 is the degradation index in correlation with 0.05 for dextran. The rate of degradation can be decreased or managed by differing degrees of synthetic modification [81]. A portion of the significant regions wherein pullulan is examined are discussed about in the accompanying area. Derivatization of pullulan is a simple procedure to upgrade its action and to enlarge its applications in the biomedical field. Pullulan derivatives have been obtained by graft copolymerization with diverse chemical moieties on its backbone [82]. The hydroxyl groups present on the pyranose ring of pullulan offer many sites for derivatization. Distribution of the hydroxyl groups gives the best possible appearance to the compound. For every repeating unit, pullulan has nine hydroxyl groups; it tends to be derivatized in different structures by substituting these hydroxyl groups to upgrade its utility in biomedical applications. The derivatization differs as indicated by the solvent and reagent nature [24]. Different derivatives are synthesized through various reactions such as copolymerization, esterification, chlorination, etherification, sulfation, amidification, and oxidation [83].
Combinatorial Approach to Polymer Design for Nanomedicines
Published in Vladimir Torchilin, Handbook of Materials for Nanomedicine, 2020
Amit Singh, Meghana Rawal, Mansoor M. Amiji
Conceptually, nanoparticles should be envisioned as a 3D construct of multiple “building blocks,” each having a key role in the architecture and imparting a desired property to the final drug product. Building such a complex architecture with controlled properties requires precision in design and engineering. Therefore, recent efforts in discovery of polymeric drug delivery systems have relied on a more customizable and modular platform technology using combinatorial design. The concept of combinatorial design is not new and has been extensively utilized in drug discovery through high-throughput screening. This approach utilizes computational methods to generate a library of compounds that are then synthesized and mapped by systematic analysis of experimental data to identify positive “hits.” The same principle has been extended to material discovery where a suitable polymer backbone is modified with different chemical entities to generate a library of derivatives with a varying range of physicochemical properties. These derivatives can be screened based on the prior knowledge of drug candidate for target disease to study the structure–property relationship and choose the optimal combination of derivatives to devise the suitable drug delivery system.
Remediation of Oil-contaminated Sediments Using Microemulsions: A Review
Published in Soil and Sediment Contamination: An International Journal, 2021
Suelem Dela Fonte, Cibele Silva, Luiz Carlos Santos, George Simonelli
Worldwide, petroleum is the most widely used fossil fuel due to its diversity in the applications of its derivatives, ranging from everyday activities to industry, such as the production of plastics, asphalt, and fuels. The growing world demand for oil has progressively driven the increase in production in onshore and offshore operations. However, during exploration and production activities, oil spills can occur, which reach the soil and sand, contaminating them (Oliveira et al. 2014).
Surfactant assisted production of ricinoleic acid using cross-linked and entrapped porcine pancreas lipase
Published in Journal of Dispersion Science and Technology, 2021
Debapriya Bhattacharjee, Debajyoti Goswami
Ricinoleic acid or 12-hydroxy-cis-9-octadecenoic acid is an industrially important fatty acid. Its derivatives are used in preparation of surfactant, soap, plasticizer, lubricant, ingredient of chocolate, foam stabilizer, thermosetting acrylics, etc.[1,2] It occupies 90% of fatty acid profile of castor oil, its main source. Ricinoleic acid can be obtained on hydrolysis of castor oil. The conventional hydrolysis processes like base catalyzed process and high temperature splitting process have certain disadvantages like formation of ricinoleic acid estolide, an unwanted by-product[1] and generation of characteristic odor and colour.[3] Hydrolysis involving a biocatalyst (an enzyme called lipase) has certain advantages like moderate process conditions (ambient or slightly higher temperature, atmospheric pressure) and excellent product purity over conventional processes. Lipase is an industrially important enzyme which acts as a catalyst in reactions like hydrolysis, esterification, alcoholysis, etc.[4–7] Lipases often have substrate and/or product specificity coupled with a high enantioselectivity and regioselectivity;[4] Goswami et al.[5] applied free Candida rugosa lipase (CRL) in castor oil hydrolysis to ricinoleic acid. Free lipase easily gets denatured by shear force caused by stirring and at temperature moderately above the ambient level. In presence of Span 80 (nonionic surfactant), free CRL showed better catalytic ability to produce ricinoleic acid from castor oil.[8] Immobilized lipase is better than free lipase as a catalyst for its higher thermostability, recyclability, etc. Wu et al.[9] noted that entrapment was an effective immobilization technique due to its simple operation, cost effectiveness and lower leakage tendency of enzyme; though the overall enzyme activity decreased due to increase in mass transfer resistance. Cross-linking of lipase with bifunctional reagents like glutaraldehyde, followed by entrapment, can effectively enhance its activity. Entrapment leads to capture of lipase molecules within a polymer matrix. Cross-linking between lipase and glutaraldehyde molecules leads to formation of stable molecular aggregates. Abdulla and Ravindra[6] observed that cross-linked and entrapped lipase had lower leakage and higher catalytic ability compared to only entrapped lipase. Based on these findings, cross-linking followed by entrapment was adopted as immobilization method in this study.