40299-04-5Relevant academic research and scientific papers
EPOXY-CONTAINING POLY(ESTER AMIDES) AND METHODS OF USE
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Page/Page column 48-49, (2010/11/30)
The invention provides aliphatic epoxy-containing PEA polymer compositions with film-forming properties. The aliphatic epoxy di-acids used in the invention PEA compositions include non-toxic fatty aliphatic epoxy homologs. A second, C-protected L-lysine-based monomer can be introduced into the polymer to provide additional chain flexibility. The invention PEA polymer compositions are useful for delivery of bioactive agents when administered internally or used in the manufacture of implantable medical devices. Biodegradable hydrogels can be made using the invention epoxy-containing PEAs.
Chromatographic approach to the measurement of the interstrand distance for some chiral bonded phases
Pirkle, William H.,Readnour, Robin S.
, p. 16 - 20 (2007/10/02)
A series of homologous N,N′-bis(2,4-dinitrophenyl)-α,ω-diaminoalkanes (bis-DNP's) was chromatographed at various temperatures on π-basic chiral stationary phases derived from N-(2-naphthyl)alanine in order to determine the enthalpy and entropy of adsorption. The number of methylene groups in the bis-DNP's influences the ability of the terminal π-acidic groups to interact simultaneously with neighboring strands of stationary phase, a process termed "bridging". When the number of methylene groups is optimal for bridging, the enthalpy of adsorption is most exothermic. The length of the bis-derivative required for optimal bridging is related to the interstrand distance. Optimal bridging occurs for the bis-DNP's having five methylene groups regardless of the extent of surface coverage of the silica for the surface coverage range investigated. This suggests that the strands are not randomly spaced on the silica, with interstrand distance being influenced only by surface coverage, but are instead clustered, the clusters having similar distributions of interstrand distances. Adsorption is more exothermic for phases of high surface coverages than for low. If Interstrand spacing is independent of surface coverage but surface coverage affects the enthalpy of adsorption, then surface coverage must influence the cluster size, which then influences the average extent of solvation of a strand of bonded phase.
