294
chitosan, for which the adsorption and release of a model drug (ketoprofen) were
evaluated some time ago (Prabaharan and Mano 2005). Although cyclodextrin adds
new drug inclusional properties to the polycationic polymer, a decrease in mucoadhesion of cyclodextrin-chitosan was observed, an effect attributed to the increase in
the chain compaction caused by the cyclodextrin grafting (Venter et al. 2006). More
recently, cellulosic substrates (uncoated and crepe paper and a medical bandage)
were grafted by a cyclodextrin polymer to sustain the release of antibacterial agents
(Cusola et al. 2013). Besides those polysaccharides, other materials such as
poly(hydroxyethylmethacrylate) have also been grafted with β-cyclodextrin for its
application in soft contact lenses conservation liquids and to sustain drug delivery
in the lacrimal fluid (dos Santos et al. 2009). The use of some cyclodextrin polymers
for therapeutics delivery was patented in 2013 (Cheng et al. 2013).
In the turn of the century, a new class of polymers for the delivery of macromolecular therapeutics arose (Gonzalez et al. 1999). Polymeric vectors for gene
delivery and gene therapy, in contrast to viral vectors, avoid an immune response,
and, in addition, they are capable of carrying nucleic acids of virtually any size.
Thus, cationic cyclodextrin polymers used to bind deoxyribonucleic acid showed
comparable or even better results to those obtained for polyethyleneimine. Thus,
low molecular weight poly(ethylenimine) cross-linked by (2-hydroxypropyl)-βcyclodextrin or (2-hydroxypropyl)-γ-cyclodextrin demonstrated its lower cytotoxicity and higher transfection efficiency for the delivery of plasmid
deoxyribonucleic acid compared with those of poly(ethylenimine) (Huang et al.
2006). Another significant achievement has been, for instance, the use of a specific functional group such as folic acid grafted to poly(ethyleneimine)-cyclodextrin carriers, to target the tumor cells (Yao et al. 2009). Intranasal mRNA
vaccination with the aid of a cationic cyclodextrin-poly(ethyleneimine) conjugate, capable of overcoming the nasal epithelial barrier, has also been recently
proposed (Li et al. 2016b).
Drug release behavior can be modulated with the aid of stimuli-responsive polymers. Among them, poly(N-isopropylamide) has attracted much attention in the
recent past because of its sharp and somewhat tuneable phase transition close to
32 °C, ideal for injectable clinical applications. Moreover, the design of interpenetrated networks permits to combine the temperature responsiveness of poly(Nisopropylamide) gels with the inclusional capabilities of cyclodextrin networks. For
instance, a semi-interpenetrated network was prepared incorporating a water- soluble
cyclodextrin-epichlorohydrin polymer into the poly(N-isopropylamide) hydrogel to
find that the release rate of the model drug (ibuprofen) from the β-cyclodextrin containing gel was slower and the release time was greatly prolonged (Zhang et al.
2005). Another semi-interpenetrated network was prepared by the radical polymerization and cross-linking of N-isopropylacrylamide in the presence of β-cyclodextringrafted polyethylenimine. The propranolol release rate from the semi-interpenetrated
network matrix was retarded because of the formation of complexes between the
drug and the β-cyclodextrin moieties, and the release kinetics could be tuned by
controlling the environmental temperature (Zhang et al. 2008). Interpenetrated
M. Petitjean et al.
chitosan, for which the adsorption and release of a model drug (ketoprofen) were
evaluated some time ago (Prabaharan and Mano 2005). Although cyclodextrin adds
new drug inclusional properties to the polycationic polymer, a decrease in mucoadhesion of cyclodextrin-chitosan was observed, an effect attributed to the increase in
the chain compaction caused by the cyclodextrin grafting (Venter et al. 2006). More
recently, cellulosic substrates (uncoated and crepe paper and a medical bandage)
were grafted by a cyclodextrin polymer to sustain the release of antibacterial agents
(Cusola et al. 2013). Besides those polysaccharides, other materials such as
poly(hydroxyethylmethacrylate) have also been grafted with β-cyclodextrin for its
application in soft contact lenses conservation liquids and to sustain drug delivery
in the lacrimal fluid (dos Santos et al. 2009). The use of some cyclodextrin polymers
for therapeutics delivery was patented in 2013 (Cheng et al. 2013).
In the turn of the century, a new class of polymers for the delivery of macromolecular therapeutics arose (Gonzalez et al. 1999). Polymeric vectors for gene
delivery and gene therapy, in contrast to viral vectors, avoid an immune response,
and, in addition, they are capable of carrying nucleic acids of virtually any size.
Thus, cationic cyclodextrin polymers used to bind deoxyribonucleic acid showed
comparable or even better results to those obtained for polyethyleneimine. Thus,
low molecular weight poly(ethylenimine) cross-linked by (2-hydroxypropyl)-βcyclodextrin or (2-hydroxypropyl)-γ-cyclodextrin demonstrated its lower cytotoxicity and higher transfection efficiency for the delivery of plasmid
deoxyribonucleic acid compared with those of poly(ethylenimine) (Huang et al.
2006). Another significant achievement has been, for instance, the use of a specific functional group such as folic acid grafted to poly(ethyleneimine)-cyclodextrin carriers, to target the tumor cells (Yao et al. 2009). Intranasal mRNA
vaccination with the aid of a cationic cyclodextrin-poly(ethyleneimine) conjugate, capable of overcoming the nasal epithelial barrier, has also been recently
proposed (Li et al. 2016b).
Drug release behavior can be modulated with the aid of stimuli-responsive polymers. Among them, poly(N-isopropylamide) has attracted much attention in the
recent past because of its sharp and somewhat tuneable phase transition close to
32 °C, ideal for injectable clinical applications. Moreover, the design of interpenetrated networks permits to combine the temperature responsiveness of poly(Nisopropylamide) gels with the inclusional capabilities of cyclodextrin networks. For
instance, a semi-interpenetrated network was prepared incorporating a water- soluble
cyclodextrin-epichlorohydrin polymer into the poly(N-isopropylamide) hydrogel to
find that the release rate of the model drug (ibuprofen) from the β-cyclodextrin containing gel was slower and the release time was greatly prolonged (Zhang et al.
2005). Another semi-interpenetrated network was prepared by the radical polymerization and cross-linking of N-isopropylacrylamide in the presence of β-cyclodextringrafted polyethylenimine. The propranolol release rate from the semi-interpenetrated
network matrix was retarded because of the formation of complexes between the
drug and the β-cyclodextrin moieties, and the release kinetics could be tuned by
controlling the environmental temperature (Zhang et al. 2008). Interpenetrated
M. Petitjean et al.