Poly[(amino acid ester)phosphazenes]: Synthesis, Crystallinity, and Hydrolytic Sensitivity in Solution and the Solid State

Abstract

Fifteen different poly[ (amino acid ester)phosphazenes] were synthesized to study their crystalline character and hydrolysis behavior in the solution and solid states. The polyphosphazenes synthesized were poly [ bis(methy1 glycinat-N-y1)phosphazenel , poly[ bis(ethy1 glycinat-N-y1)phosphazenel , poly [bis(tertbutyl glycinat-N-yl)phosphazene], poly[bis(benzyl glycinat-N-yl)phosphazene], poly[bis(methyl alaninat-N-yl)phosphazene], poly[bis(ethyl alaninat-N-yl)phosphazene], poly[bis(tert-butyl alaninat-N-y1)phosphazene] , poly[ bis( benzyl alaninat-N-yl) phosphazene] , poly [bis(methyl valinat-N-yl)phosphazene] , poly-[bis(ethyl valinat-N-y1)phosphazenel , poly [bis(tert-butyl valinat-N-y1)phosphazenel , poly[bis(benzyl valinat-N-y1)phosphazenel , poly[bis(methyl phenylalaninat-N-y1)phosphazenel , poly[bis(ethyl pheny1alaninat-Ny1)phosphazenel , and poly [bis(tert-butyl phenylalaninat-N-y1)phosphazenel . The fully-substituted polymerswere obtained by treatment of poly(dich1orophosphazene) with a large excess of the appropriate amino acid ester. Several of these polymers were crystalline as measured by differential scanning calorimetry and by polarized optical microscopy. Hydrolysis studies were performed to estimate the rates of decomposition of the polymers and the duration over which the polymers maintained their structural integrity. The polymers are potential biomedical materials.

Polyphosphazene/Nano-Hydroxyapatite Composite Microsphere Scaffolds for Bone Tissue Engineering

“…3,7 Hexachlorotriphosphazene was purified by recrystallization, followed by sublimation. This was then polymerized under vacuum in a sealed silica tube at 255 °C to obtain poly (dichlorophosphazene) (PDCP), followed by sublimation of unreacted hexachlorocyclotriphosphazene.…”

“…Both 31 P and 1 H NMR chemical shifts recorded for the polymers under study match the literature values. 3 Molecular weights of the polymers were measured via gel permeation chromatography (GPC) by use of a Hewlett Packard LC 1100 series. Molecular weights were compared to polystyrene standards.…”

In situ Porous Structures: A Unique Polymer Erosion Mechanism in Biodegradable Dipeptide‐Based Polyphosphazene and Polyester Blends Producing Matrices for Regenerative Engineering

“…[ 8 ] The degradation mode and pattern of the polymer can also be tuned effi ciently by incorporating different side groups. [ 9 ] For example, amino acid ester side groups confer hydrolytic instability to the polymer while addition of phenylphenoxy side groups increases its hydrophobicity. By examining nature's own chemistry hydrogen bonding signifi cantly contributes to formation of unique and highly defi ned architectures in biological systems such as in the folding of proteins.…”

Synthesis, characterization, and in vitro degradation of star‐shaped P(ε‐caprolactone)‐b‐poly(L‐lactide)‐b‐poly(D,L‐lactide‐co‐glycolide) from hexakis [p‐(hydroxymethyl)phenoxy]cyclotriphosphazene initiator

“…[43][44][45] Allcock and Pucher reported some of phosphazene polymers that could be used as drug carriers for delivery systems. 46 Cohen et al synthesized a novel matrix from ionically crosslinkable polyphosphazene. 47 Cyclotriphosphazenes exhibit useful thermal properties and excellent biocompatibility.…”