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Resin Used (resin + used)
Selected AbstractsIon-exchange resins as drug delivery carriersJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2009Xiaodi Guo Abstract There are many reports in the literature referring to the utilization of drug bound to ion-exchange resin (drug,resinate), especially in the drug delivery area. Ion-exchange resin complexes, which can be prepared from both acidic and basic drugs, have been widely studied and marketed. Salts of cationic and anionic exchange resins are insoluble complexes in which drug release results from exchange of bound drug ions by ions normally present in body fluids. Resins used are polymers that contain appropriately substituted acidic groups, such as carboxylic and sulfonic for cation exchangers; or basic groups, such as quaternary ammonium group for anion exchangers. Variables relating to the resin are the exchange capacity; degree of cross-linking, which determines the permeability of the resin, its swelling potential, and the access of the exchange sites to the drug ion; the effective pKa of the exchanging group, which determines the exchange affinity; and the resin particle size, which controls accessibility to the exchange ions. In this review, the properties of ion-exchange resins, selection of drugs that lend themselves to such an approach, selection of the appropriate resin, preparation of drug,resinate, evaluation of drug release, recent developments of drug,resinates, and applications are discussed. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:3886,3902, 2009 [source] Sensitivity to Myroxylon pereirae resin (balsam of Peru).CONTACT DERMATITIS, Issue 6 2005A study of 50 cases The Myroxylon pereirae resin (MP; balsam of Peru) is a natural resin used in the local treatment of burns and wounds. M. pereirae extracts and distillates are very often contained in a wide range of cosmetic products and causes frequently allergic contact dermatitis , to the extent of being considered an allergy marker to perfumes. We have carried out a retrospective study of 863 patients who have been submitted to patch tests from January 2002 to June 2004. A total of 50 patients were positive to MP. Thus, the prevalence was 5.79%, slightly higher in men (7.32%) than in women (4.91%). The positive patch tests were relevant in 64%. Over the last years, it appears that there is a clear increase of the prevalence of the sensitization to MP in all the studies published. We observe an increase of the prevalence especially in aged patients, where the sensitization is linked with the use of topical medications secondary to stasis dermatitis. The high frequency of allergy to MP in our area might be associated with manipulation of citrus fruits. The increasing use of cosmetic products by the male population can also be held responsible for the higher sensitization rate in this group of patients. [source] Sorption properties of the iminodiacetate ion exchange resin, amberlite IRC-718, toward divalent metal ionsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Charef Noureddine Abstract The sorption properties of the commercially available cationic exchange resin, Amberlite IRC-718, that has the iminodiacetic acid functionality, toward the divalent metal-ions, Fe2+, Cu2+, Zn2+, and Ni2+ were investigated by a batch equilibration technique at 25°C as a function of contact time, metal ion concentration, mass of resin used, and pH. Results of the study revealed that the resin exhibited higher capacities and a more pronounced adsorption toward Fe2+ and that the metal-ion uptake follows the order: Fe2+ > Cu2+> Zn2+ >Ni2+. The adsorption and binding capacity of the resin toward the various metal ions investigated are discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Benzhydrylamine linker grafting: a strategy for the improved synthesis of C -terminal peptide amides,JOURNAL OF PEPTIDE SCIENCE, Issue 10 2010Dianne Alewood Abstract The standard p -MBHA resin used during Boc-chemistry synthesis of peptides carrying C -terminal carboxamides is compromised by batch-to-batch variations in its performance. This can cause artificially ,difficult' couplings during peptide chain assembly, which may ultimately lead to failed syntheses given the inability to achieve acceptable coupling yields. To overcome these problems, we have developed a new approach by grafting a functionalized benzhydrylamine linker onto well-characterized and well-performing PAM resins. We combine optimized Boc-chemistry, high-performing PAM resins and new benzhydrylamine-based linkers to achieve improved syntheses of peptide amides. Here we present the synthesis of two new benzhydrylamine linkers and their attachment to selected PAM resins. This novel solid support was evaluated through the synthesis of selected ,difficult' conotoxins and monitoring the coupling efficiency using quantitative ninhydrin assay. The results show a superior performance of the novel linker solid support compared to the standard p -MBHA resins routinely used. In summary, we describe an alternative linker-resin system that allows improved access to C -terminal amide peptides employing Boc/Bzl chemistry. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. [source] Investigation of the relationships between die build up and die swellPOLYMER ENGINEERING & SCIENCE, Issue 2 2009Todd A. Hogan Die build up (DBU) is a common problem encountered during extrusion of polymers where material accumulates around the die exit and may cause defects in the surface of the product. This study was initiated to better understand the fundamental relationships between DBU and die swell. The study was conducted on a strand die extrusion system using an ethylene-octene polyolefin elastomer resin. This study demonstrated that die swell is not a root cause of DBU. It was shown that at constant shear rate, increasing the die L/D ratio results in an increase in DBU, while die swell decreases. The important variables influencing DBU for the resin used in this study were: the shear rate or shear stress in capillary portion of the die, the nominal residence time that the resin is exposed to the high shear stress in the die capillary, and the concentration of oligomers present in the resin or generated during processing. These data support the conclusion that DBU is due to the shear-induced migration of oligomeric species in the polymer to the die surface. Higher shear rates and stresses in the die promote this migration and result in a higher concentration of oligomeric species near the die wall. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers [source] Effect of Mounting Material Compliance on Nanoindentation Response of Metallic Materials,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2009Grant A. Crawford Nanoindentation is an important and versatile technique for probing the properties of materials on the nanoscale. There are many factors that may affect nanoindentation measurements. One factor is the added compliance associated with mounting resins used to fix nanoindentation samples in place. We report on the effect of specimen mounting resin compliance on nanoindentation results. [source] | |||||||||||||