Biomedical Engineering Reference
In-Depth Information
O
O
O
OH
O
NH
O
O
O
H
OH
O
O
OH
O
O
FIGURE 6.30
Structure of paclitaxel.
proliferation through centrosomal impairment (Kukreja et al., 2008; Abal et al., 2003). It is
a strong antiproliferative and was first used as an anticancer drug (Daemen and Serruys,
2007). However, it is potentially cardiotoxic, and the dose at which paclitaxel can be deliv-
ered safely has yet to be resolved (Am. Soc. Health Syst. Pharm. 1989; Rowinsky and
Donehower, 1995).
Controlled Release
The controlled release coating generally comprises two materials, the active pharmaceuti-
cal and the matrix, although in some cases the drug is coated onto the stent alone. In this
section, we will describe the controlled release characteristics of polymer-based matrices.
Nonpolymeric reservoirs will be discussed later in the chapter (Figure 6.31).
Methods of controlled release can be broadly classified into physical and chemical
mechanisms in terms of the nature of the interaction between the drug and the matrix
(Acharya et al., 2006). When the drug is mixed with the matrix using physical means, the
Sirolimus and analogues
G
0
-Phase
Nc replication
M-Phase
Cell division
Paclitaxel
FIGURE 6.31
Effects of sirolimus analogues and paclitaxel on the cell cycle.
