ABSTRACT
Zwitterionic sulfobetaine-based monolithic stationary phases have attracted increasing attention for their use in hydrophilic interaction chromatography.In this study,a novel hydrophilic polymeric monolith was fabricated through photo-initiated copolymerization of 3-(3-vinyl-1-imidazolio)-l-propanesulfonate(SBVI)with pentaerythritol triacrylate using methanol and tetrahydrofuran as the porogenic system.Notably,the duration for the preparation of this novel monolith was as little as 5 min,which was significantly shorter than that required for previously reported sulfobetaine-based monoliths prepared via conventional thermally initiated copolymerization.Moreover,these monoliths showed good morphology,permeability,porosity(62.4％),mechanical strength(over 15 MPa),column efficiency(51,230 plates/m),and reproducibility(relative standard deviations for all analytes were lower than 4.6％).Mechanistic studies indicated that strong hydrophilic and negative electrostatic interactions might be responsible for the retention of polar analytes on the zwitterionic SBVI-based monolith.In particular,the resulting monolith exhibited good anti-protein adhesion ability and low nonspecific protein adsorption.These excellent features seem to favor its application in bioanalysis.Therefore,the novel zwitterionic sulfobetaine-based monolith was successfully employed for the highly selective separation of small bioactive compounds and the efficient enrichment of N-glycopeptides from complex samples.In this study,we prepared a novel zwitterionic sulfobetaine-based monolith with good performance and developed a simpler and faster method for preparation of zwitterionic monoliths.
ABSTRACT
Recently, worldwide extensive attention is being paid in exploration and exploitation of pharmaceutical excipients from natural resource. Various natural polysaccharides have been significantly reported as prospective drug delivery carriers. These natural gums are preferred over synthetic polymers because of their biocompatibility, low cost, free availability and biodegradability. But due to variable chemical composition, microbial load, microbial growth and change in viscosity upon aging, acceptability is low compared to commercial synthetic products. Tailoring or modification may be an approach to make them smart as drug carriers specially in order to modulate the site of drug release and it’s kinetic. The chemical modification of okra gum (OG) was the main objective of the present study in order to make it potential mucoadhesive for the application in mucoadhesive drug delivery. In this study, methacrylic acid was grafted onto okra gum. At first, okra gum has been isolated from the fruits of Hibiscus esculentus. Poly (methacrylic acid)-grafted-okra gum (PMAc-g-OG) was synthesised employing a microwave-promoted and redox-initiated method. Potassium persulphate was used as free- radical-initiator. Methacrylic acid was mixed to 1% solution of OG and then 30 ml of potassium persulphate aqueous solution was added to the previous mixture along with continuous stirring. The mixture was exposed to microwave in a domestic micro-oven. The mixture was kept overnight and the copolymer was collected and purified using acetone and aqueous methanol (30% v/v) subsequently. The copolymer was charateized by elemental analysis, FTIR, DSC-TGA, and 13C NMR study. Ex-vivo mucoadhesion test was performed using goat stomach. A highest % grafting of 448.32% was found in the synthetic procedure employed in the study. The characterization studies also substantiate the successful grafting. Ex-vivo mucoadhesion study also showed excellent mucoadhesive capacity over a period of 16 hours. The study exhibited that the method employed was very simple, less time consuming, one-pot and without N2 atmosphere. The copolymer also exhibited excellent mucoadhesivity which might be applied in different mucoadhesive drug delivery systems such as prolonged release gastroretentives, buccal gels, etc.
ABSTRACT
PURPOSE: Polymethyl methacrylate (PMMA) is the most commonly used denture base material despite typically low in strength. The purpose of this study was to improve the physical properties of the PMMA based denture base resins (QC-20, Dentsply Ltd., Addlestone, UK; Stellon, AD International Ltd, Dentsply, Switzerland; Acron MC; GC Lab Technologies Inc., Alsip, Japan) by copolymerization mechanism. MATERIALS AND METHODS: Control group specimens were prepared according to the manufacturer recommendations. In the copolymer groups; resins were prepared with 5%, 10%, 15% and 20% acrylamide (AAm) (Merck, Hohenbrunn, Germany) content according to the moleculer weight ratio, respectively. Chemical structure was characterized by a Bruker Vertex-70 Fourier transform infrared spectroscopy (FTIR) (Bruker Optics Inc., Ettlingen, Germany). Hardness was determined using an universal hardness tester (Struers Duramin, Struers A/S, Ballerup, Denmark) equipped with a Vickers diamond penetrator. The glass transition temperature (Tg) of control and copolymers were evaluated by Perkin Elmer Diamond DSC (Perkin Elmer, Massachusetts,USA). Statistical analyses were carried out using the statistical package SPSS for Windows, version 15.0 (SPSS, Chicago, IL, USA). The results were tested regarding the normality of distribution with the Shapiro Wilk test. Data were analyzed using ANOVA with post-hoc Tukey test (P<.01). RESULTS: The copolymer synthesis was confirmed by FTIR spectroscopy. Glass transition temperature of the copolymer groups were higher than the control groups of the resins. The 10%, 15% and 20% copolymer groups of Stellon presented significantly higher than the control group in terms of hardness. 15% and 20% copolymer groups of Acron MC showed significantly higher hardness values when compared to the control group of the resin. Acrylamide addition did not affect the hardness of the QC-20 resin significantly. CONCLUSION: Within the limitation of this study, it can be concluded that copolymerization of PMMA with AAm increased the hardness value and glass transition temperature of PMMA denture base resins.