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Chakraborty S.,Ateneo de Manila University | Razonabe C.C.,Ateneo de Manila University | Chua M.T.,Ateneo de Manila University | Chua M.T.,Philippine Institute of Pure and Applied Chemistry
International Journal of Nano and Biomaterials | Year: 2014

A novel method for the synthesis of nano size molecularly imprinted poly(acrylic acid) (PAA) by reverse microemulsion technique has been reported. Molecularly-imprinted PAA were also synthesised by bulk polymerisation. Levofloxacin (LOfx) (S ofloxacin) was used as the template for imprinting. Scanning electron micrograph and dynamic light scattering profile revealed that emulsion polymerisation resulted in nano size molecularly-imprinted polymer (MIP) with narrow size distribution whereas bulk polymerisation resulted in irregular shaped micron size particles. Rebinding of LOfx was highest for nano MIPs as compared to micron MIPs and the non-imprinted polymers (NIP). Imprinting factor which indicates selective binding capacity was maximum for the nano system both in water as well as in acetonitrile. Circular dichroism spectroscopy showed that nano and micron size MIPs could selectively bind to chiral LOfx from its racemic mixture (R, S ofloxacin). However, selectivity of nano MIPs was superior to micro MIPs. TLC plate prepared using nano MIP as the stationary phase could also isolate LOfx from Ofx as two distinct spots on the TLC plate, well separated spots were not visible when microsize or non-imprinted polymers were used as the stationary phase. Copyright © 2014 Inderscience Enterprises Ltd. Source


Dalafu H.,Ateneo de Manila University | Chua M.T.,Philippine Institute of Pure and Applied Chemistry | Chakraborty S.,Ateneo de Manila University
ACS Symposium Series | Year: 2010

Interpenetrating network (IPN) of κ-carrageenan and poly(acrylic acid) was fabricated. Polyacrylic acid was synthesized as well as crosslinked in the presence of κ-carrageenan followed by crosslinking the κ-carrageenan in the presence of sodium ion. In order to fabricate glycidyl trimethyl ammonium chloride(Quat 188) modified κ-carrageenan IPN, κ-carrageenan was first coupled with Quat 188 in the presence of base followed by the fabrication of IPN. Analysis of the DSC thermogram revealed that the rigidity of the IPN improved with the increment of the κ-carrageenan content. Modification of κ-carrageenan further increased the rigidity. The IPNs swelled almost 300% in aqueous medium to form the hydrogels. Swelling was more pronounced in basic pH than in acidic pH. These hydrogels could incorporate approximately 94% of the prototype drug AgNO3 in 30min from aqueous medium. © 2010 American Chemical Society. Source


Sala L.A.G.,Ateneo de Manila University | Villanueva K.M.A.,Philippine Institute of Pure and Applied Chemistry | Chua M.T.,Ateneo de Manila University | Chua M.T.,Philippine Institute of Pure and Applied Chemistry | Chakraborty S.,Ateneo de Manila University
Materials Science and Engineering C | Year: 2012

Novel glycerol crosslinked poly(methyl methacrylate)(PMMA) was synthesized in one step in the presence of cocktail of chemical initiator and the biocatalyst Novozym 435 under mild reaction conditions. The objective of the study was to investigate the feasibility of glycerol to crosslink PMMA by biocatalytic route and to explore glycerol crosslinked PMMA as controlled release vehicle Effect of reaction time, temperature, glycerol to methylmethacrylate ratio, and methacrylate to toluene ratio was studied. Glycerol crosslinked PMMA swelled 289(± 9)% in acetone and collapsed when immersed in water and in hexane. Swelling and shrinking of glycerol crosslinked PMMA was reversible in nature. Nanoparticles of glycerol crosslinked poly(methyl methacrylate) were synthesized by nanoprecipitation technique. The particles were spherical and of nanosize. The nanoparticles were used for the encapsulation and release of mosquito repellent N,N-diethyl-m-toluamide. Nanoparticles could encapsulate 8.5 mg of repellant in 4 h. The repellant got released from the nanoparticles at a controlled rate for a prolonged time interval. Release was more pronounced in deionized water and pH 7 buffer than in acetone. Addition of 1% NaCl further improved the release profile. 80% of encapsulated repellant was released from the nanoparticles in pH 7 buffer with 1% NaCl. © 2012 Elsevier B.V. Source

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