Biomedical Engineering Reference
In-Depth Information
Hole
Strut
Cross section
FIGURE 6.19
An in-stent built hole (honeycombed) structure of matrix/drug coating in a Conor stent.
Intra-Built Holes
The Conor Medsystems stent has numerous holes (in a honeycomb arrangement) on each
strut. Each hole is filled with a mixture of drug and biodegradable polymer in a solvent,
using a piezoelectric microdispenser. The loading process is repeated on each hole as many
as 22 times, in the case of PLGA/paclitaxel in dimethyl sulfoxide (DMSO) (Finkelstein
et al., 2003). This controlled-release coating (Figure 6.19) has a limited exposed surface area
for drug release.
Intra-Built Cavity
The Janus CarboStent has deep grooves on the outer stent surface that are used to hold
tacrolimus (Acharya and Park, 2006). The stent surface is first treated with an integral
carbofilm coating, which is known to render the stent surface nonthrombogenic when in
contact with blood. The deep grooves (Figure 6.20) can load more drugs than other DES
in the similar size range, and the polymer-free drug can be loaded with promising release
profile.
Hole
Strut
Cross section
FIGURE 6.20
In-stent built cavity (deep grooves) of polymer-free drug coating in a Janus CarboStent.
