Influence of Constraints within a Cyclic Polymer on Solution Properties
Cyclic polymers with internal constraints provide new insight into polymer properties in solution and bulk and can serve as a model system to explain the stability and mobility of cyclic biomacromolecules. The model system used in this work consisted of cyclic polystyrene structures, all with a nearly identical molecular weight, designed with 0–3 constraints located at strategic sites within the cyclic polymer, with either 4 or 6 branch points. The total number of branch points (or arms) within the cyclic ranged from 0 to 18. Molecular dynamic (MD) simulations showed that as the number of arms increased within the cyclic structure, the radius of gyration and the hydrodynamic radius generally decreased, suggesting the greater number of constraints resulted in a more compact polymer chain. The simulations further showed that the excluded volume was much greater for the cyclics compared to a linear polymer at the same molecular weight. The spirocyclic, a structure consisting of three rings joined in series, ...
Md. D. Hossain; James C. Reid; Derong Lu; Zhongfan Jia; Debra J. Searles; Michael J. Monteiro
Chemokine receptor CXCR4 plays an important role in cancer cell invasion and metastasis. Recent findings suggest that anti-VEGF therapies upregulate CXCR4 expression, which contributes to resistance to antiangiogenic therapies. Here, we report the development of novel derivatives of polyeth ... mehr
The molecular structures of three parthenolide analogues, (−)-goyazensolide (1), (−)-15-deoxygoyazensolide (2), and (−)-ereglomerulide (3), isolated from the leaves of Piptocoma rufescens in a previous study were determined by X-ray analysis, and the absolute configuration of (−)-goyazensol ... mehr
The molecular integration of poorly water soluble active pharmaceutical ingredients (APIs) in a suitable polymeric matrix is a possible approach to enhance the dissolution behavior and solubility of these APIs. Like all newly developed pharmaceutical formulations, these formulations (often ... mehr