Faculty Publications
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Item Low frequency sonic waves assisted cloud point extraction of polyhydroxyalkanoate from Cupriavidus necator(Elsevier B.V., 2017) Murugesan, S.; Iyyaswami, R.Low frequency sonic waves, less than 10 kHz were introduced to assist cloud point extraction of polyhydroxyalkanoate from Cupriavidus necator present within the crude broth. Process parameters including surfactant system variables and sonication parameters were studied for their effect on extraction efficiency. Introduction of low frequency sonic waves assists in the dissolution of microbial cell wall by the surfactant micelles and release of cellular content, polyhydroxyalkanoate granules released were encapsulated by the micelle core which was confirmed by crotonic acid assay. In addition, sonic waves resulted in the separation of homogeneous surfactant and broth mixture into two distinct phases, top aqueous phase and polyhydroxyalkanoate enriched bottom surfactant rich phase. Mixed surfactant systems showed higher extraction efficiency compared to that of individual Triton X-100 concentrations, owing to increase in the hydrophobicity of the micellar core and its interaction with polyhydroxyalkanoate. Addition of salts to the mixed surfactant system induces screening of charged surfactant head groups and reduces inter-micellar repulsion, presence of ammonium ions lead to electrostatic repulsion and weaker cation sodium enhances the formation of micellar network. Addition of polyethylene glycol 8000 resulted in increasing interaction with the surfactant tails of the micelle core there by reducing the purity of polyhydroxyalkanoate. © 2017 Elsevier B.V.Item Preparation, characterization and stability evaluation of ionic liquid blended chitosan tripolyphosphate microparticles(Editions de Sante editions.de.sante@wanadoo.fr, 2019) Safdar, R.; Francisco Nirmala, N.; Iyyaswami, R.; Arunagiri, A.; Papadimitriou, S.; Murugesan, M.Recently, drug delivery systems are facing several shortcomings which demand for the development of new formulations. A new drug–solvent systems may improve the characteristics and sustained release of drugs. Investigations in this domain revealed the significance of Ionic Liquids (ILs) as active pharmaceutical ingredients for pharmaceutical applications. ILs–drug assisted carriers exhibit many unique and attractive properties which are lacking in their conventional counterparts. In this work, Chitosan (CS), a natural polymer was blended with an ammonium based IL, Tetramethylammonium hydroxide (TMAOH), and microparticles (MPs) of CS–TMAOH–TPP were synthesized by cross–linking with sodium tripolyphosphate (TPP) using ionic gelation method. The addition of TMAOH to CS enhanced the stability of MPs without affecting the particle size. FTIR analysis confirmed the structural changes whereas the FE-SEM analysis showed almost similar sizes of freeze–dried MPs as determined by Zetasizer. The morphology of the CS–TMAOH–TPP MPs was mostly similar to CS–TPP MPs. The Thermogravimetric analysis indicated that these MPs exhibit good thermal resistance. Moreover, the DSC and XRD analysis of the prepared MPs were conducted to analyze thermograms and crystallographic structure respectively. Overall, the present synthesized CS–TMAOH–TPP MPs are more stable than CS–TPP MPs, which will be useful for drug delivery applications. © 2019