Limitations of PEG in drug delivery have been reported from clinical trials. PEtOx (0.4-40 kDa) as alternative is synthesized by a living, microwave-assisted polymerization, and is directly compared to PEG of similar molar mass regarding cytotoxicity and hemocompatibility. In short-term treatments, both types of polymers are well tolerated even at high concentrations. Moderate concentration and molar mass dependent cytotoxic effects occurred only after long-term incubation at concentrations higher than therapeutic doses. PEtOx possesses not only an easy route of synthesis and beneficial physicochemical characteristics such as low viscosity and high stability, which are advantageous over PEG, but additionally in vitro toxicology comparable to PEG.

No abstract

Advances in biotechnology, proteomics, and genomics, as well as the deeper understanding of the molecular and cellular bases of pathophysiological states, have allowed the development of novel drugs such as proteins, peptides, and nucleic acids as therapeutic strategies of the future. Their application, however, requires sophisticated drug delivery systems which can be used to alter the pharmacokinetics and release characteristics of drugs, and to increase tissue specificity and biocompatibility. In this context, polymers provide the most promising avenue in drug release control due to their favorable, adjustable characteristics, and possibilities for further modification. Advances in the biomedical sciences have had a significant impact on the design and development of new and intelligent drug delivery systems for more controlled and targeted drug application. This review summarizes the status quo of polymer use for drug delivery with a special focus on structure–property relationships and gives overviews of various polymers, the relevant parameters in drug delivery and the most promising trends in the future.