Immobilization of Aminothiols on Poly(oxyalkylene phosphates). Formation of Poly(oxyethylene phosphates)/Cysteamine Complexes and Their Radioprotective Efficiency

Abstract

The necessity to apply near-toxic amounts of radioprotective drugs to achieve adequate protection during radiation treatments represents a major problem in human medicine. One of the promising strategies to suppress the toxicity of these drugs involves their incorporation into biocompatible polymers. In this study cysteamine (Cy) was attached to poly(oxyethylene phosphate), POEP, via an ionic bond. Radioprotection of E. coli B cells by this substance and its acute toxicity on male C57 BL mice were measured. The toxicity of Cy immobilized within the poly(oxyethylene phosphate) was significantly lower in comparison to pure Cy while its radioprotective efficiency remained high at half the maximum tolerable dose. The high radioprotective efficiency of the Cy/POEP complexes was further confirmed on mice at different polymer molecular weight characteristics, drug immobilization degrees, application times, and doses. It was found that POEP with molecular weight 4700 Da and containing 24% repeating units with attached Cy has the highest protection potential combined with a depot effect.

Antioxidant and Immuno-Enhancing Effects of Echinacea purpurea

“…9,10) Previous studies developed radioprotective agents to protect from the indirect effects of radiation by eliminating free radicals produced in response to radiation 2,3) and immunostimulants to inhibit immune suppression. 4,5) However, the toxicity and side effects of such agents have been critical problems.…”

Synthesis of Novel Biomimetic Zwitterionic Phosphorylcholine‐Bound Chitosan Derivative

“…To our knowledge, Antherton-Todd reaction is an efficient method for the manufacture of phosphoramidates from H-phosphates. [11] Ester exchange reaction of diphenyl phosphite (3) with 2 equiv. of choline chloride in mixed solution of pyridine and DMSO produced dicholinyl phosphite dichloride (4) ( 31 P NMR 10.14 ppm), and the following Antherton-Todd reaction of 4 with 6-O-trityl chitosan (2) in isopropyl alcohol/DMA in the presence of Et 3 N and CCl 4 under mild conditions yielded N-bis(phosphorylcholinyl) 6-O-trityl chitosan, and the following removal of 6-O-triphenylmethyl in formic acid led to 5 ( 31 P NMR 9.92 ppm).…”

Novel pH responsive luminescent poly(oxyethylene phosphate) tris(β-diketonate) europium (III) complexes

“…The transesterification was carried out according to reference [19][20][21][22]. 53.04 g (0.265 mol) of PEG 200 and 58.37 g (0.530 mol) of dimethylphosphonate were placed in a three-necked flask equipped with a magnetic stirrer, thermometer, and a condenser.…”