Polymer device degradation

Molecular and multi-scale modelling methods of polymer device degradation... 

The polymer should be dissolved at room temperature [28]. Magnetic stirring devices or laboratory shakers are recommended to aid dissolution. Excessive temperature or ultrasonic devices may cause the polymer to degrade. Polystyrene solutions prepared with solvents such as THF are very stable, as long as MW < 500,000 g mol 1. However, it is a good practice to analyze polymer solutions within 24 hr of their preparation [28]. 

Based on the above reasons, polymers possessing a variety of degradation rates and mechanisms have been developed however, hydrolysis still remains the predominant degradation mechanism for polymers that are most commonly used in drug delivery applications. Many polymers that are susceptible to hydrolysis, for example, the polyesters PLA and PLG, degrade by random hydrolysis that takes place homogeneously throughout the bulk of the polymer device. In contrast, other classes of polymers, such as the polyanhydrides and polyorthoesters, have been developed in an attempt to yield hydrolysis only at the outer surface of the device that is exposed directly... 

For the biomedical applications and development of drug delivery systans, polymers that have already received regulatory approval are mostly used, apart from polymer physicochonical properties such as bulk hydrophilidty, morphology, and structure, solute solubility in polymer and degradation rate of both the polymer and the device are to be kept in mind for the selection of proper polymers. 

---