Viagra Pharmacy: In the current study, we chose PCL for several reasons

There are five biodegradable polymers that have been approved by US Food and Drug Administration for making medical devices, and there are several studies of biodegradable trachea stents in rat or rabbit models that involved mainly materials of polydioxanone, poly(L-lactide), and PLGA. In the current study, we chose PCL for several reasons. First, PCL degrades at a slower pace than other biodegradable polymers, such as poly(L-lactide) or PLGA and their copolymers, and can, therefore, be used in drug-delivery devices that remain active for > 1 year. 

The experimental result of our previous study suggested that stent degradation was minimal, and the mechanical strength was well preserved in vivo at the end of 33 weeks. In Viagra Pharmacy 10% discount on all Sildenafil products! Click here for more info.Second, PCL is a semicrystalline polymer with a low melting point (59-64°C) and exhibits good flexibility at room temperature and at 37°C. It also exhibits the ability to undergo repeated dynamic shape changes without exerting too much force on the airway wall or succumbing to stress fracture. 

This would avoid the occurrence of stent fragmentation. Furthermore, stents with good flexibility are more easily manipulated and deployed with minimal invasion. The concept of a drug-eluting stent is not new, and there are many successful examples in the cardiology field, yet the application of a trachea stent is limited. Heo et al reported in vitro results of nanofiber-coated, indomethacin-eluting metallic stents for trachea regeneration. 

Whether such a concept could be further applied in anticancer drugs remained controversial. One of the major concerns is the unpredictable local and systemic toxicity brought on by the anticancer drug if the release is not controllable. Generally, the drug release from biodegradable devices has three different stages of release kinetics: an initial burst, a diffusion-controlled release, and a degradation-controlled release. 

Luckily, we only noted a mild initial burst release in our in vitro observations. This will eliminate the possible risk of toxicity associated with the burst release of cisplatin. Theoretically, the initial burst can be further reduced by using multilayer coatings, which is because the hydrophobicity of PLGA limits the water uptake of thin films to about 2% and reduces the rate of backbone hydrolysis. The presence of multilayer coatings also provides barriers for each individual layer and slows down its release rate, which in turn will minimize the initial burst of the drug release. In addition, we could also adjust the release period by changing the ratio of PLGA/cisplatin and drug loading percentage.