6
et al. 2016). Thus, an important trend in the fields of biomedicine and food nanoencapsulation is the development of vehicles capable of drug delivery and release
(Gutiérrez and Álvarez 2017; Gutiérrez 2018a).
Polymers with injectable, biocompatible and biodegradable properties emerge as
promising candidates to meet these needs since they have the ability to modulate the
toxicity of the target molecules, prolong residence time in the blood, improve water
solubility and concomitantly control the release of target molecules at the site of
interest (Soppimath et al. 2001; Rapoport, 2007; Kumari et al. 2010; Chen et al.
2011). It has been reported that the global annual sale of polymeric nanomedicine
in 2010 reached 60 billion (Zhang et al. 2010), which represents almost half of the
total sale of 121 billion of the entire nanomedicine industry (Almeida and Souto
2007). In this sense, the ability to relate the structure of polymers with the performance of delivery provides knowledge for scientists and technologists in the medicine and food industries to use tailored polymers for specific applications in the
drug delivery, as well as the nanoencapsulation of nutraceuticals.
It is therefore necessary to identify suitable polymer candidates which can be
biocompatible and biodegradable. Although there are a lot of polymers as nanocarriers. However, this chapter focuses on some selected polymers approved by the
U.S. Food and Drug Administration (FDA) for biomedical applications. In this
chapter, the preparation methodologies and physicochemical properties of these
polymers are reviewed.
2.2 Biodegradable Synthetic Polymers for Bioactive Delivery
In recent decades, a wide variety of polymers have been examined for their physicochemical properties to build delivery systems, but only a few polymers have been
approved by the FDA or the European Union (EU) for pharmaceutical uses. Most
polymers investigated cannot enter clinical phase studies due to their nonbiodegradability. In fact, large polymers for intravenous administration should be
hydrolyzed into smaller sizes enough to enter the passage of renal clearance and
spleen filtration. Otherwise, these compounds will accumulate to harmful levels. So
far, poly(propylene glycol) (PEG), poly(lactide-co-glycolic acid) (PLGA),
poly(vinyl alcohol) (PVA), poly(lactide acid) (PLA), poly(ε-caprolactone) (PCL),
poly(trimethylene carbonate) (PTMC), among others, have been used as biodegradable synthetic polymers to form delivery systems since they have no safety and
toxicity problems. The biodegradability of the polymers is a consequence of their
susceptibility to gradual degradation into smaller fractions or even monomers in
vivo, which can be subsequently metabolized by the body (Gutiérrez 2018b). This
biodegradability helps to design drug delivery systems with controllable and targetable drug release properties, as well as to reduce the possible side effects associated
with the accumulation of them.
Since polymers are composed of monomers linked by covalent bonds, therefore,
degradation of them requires the breaking of said bonds. Current knowledge about
X. Guo et al.
et al. 2016). Thus, an important trend in the fields of biomedicine and food nanoencapsulation is the development of vehicles capable of drug delivery and release
(Gutiérrez and Álvarez 2017; Gutiérrez 2018a).
Polymers with injectable, biocompatible and biodegradable properties emerge as
promising candidates to meet these needs since they have the ability to modulate the
toxicity of the target molecules, prolong residence time in the blood, improve water
solubility and concomitantly control the release of target molecules at the site of
interest (Soppimath et al. 2001; Rapoport, 2007; Kumari et al. 2010; Chen et al.
2011). It has been reported that the global annual sale of polymeric nanomedicine
in 2010 reached 60 billion (Zhang et al. 2010), which represents almost half of the
total sale of 121 billion of the entire nanomedicine industry (Almeida and Souto
2007). In this sense, the ability to relate the structure of polymers with the performance of delivery provides knowledge for scientists and technologists in the medicine and food industries to use tailored polymers for specific applications in the
drug delivery, as well as the nanoencapsulation of nutraceuticals.
It is therefore necessary to identify suitable polymer candidates which can be
biocompatible and biodegradable. Although there are a lot of polymers as nanocarriers. However, this chapter focuses on some selected polymers approved by the
U.S. Food and Drug Administration (FDA) for biomedical applications. In this
chapter, the preparation methodologies and physicochemical properties of these
polymers are reviewed.
2.2 Biodegradable Synthetic Polymers for Bioactive Delivery
In recent decades, a wide variety of polymers have been examined for their physicochemical properties to build delivery systems, but only a few polymers have been
approved by the FDA or the European Union (EU) for pharmaceutical uses. Most
polymers investigated cannot enter clinical phase studies due to their nonbiodegradability. In fact, large polymers for intravenous administration should be
hydrolyzed into smaller sizes enough to enter the passage of renal clearance and
spleen filtration. Otherwise, these compounds will accumulate to harmful levels. So
far, poly(propylene glycol) (PEG), poly(lactide-co-glycolic acid) (PLGA),
poly(vinyl alcohol) (PVA), poly(lactide acid) (PLA), poly(ε-caprolactone) (PCL),
poly(trimethylene carbonate) (PTMC), among others, have been used as biodegradable synthetic polymers to form delivery systems since they have no safety and
toxicity problems. The biodegradability of the polymers is a consequence of their
susceptibility to gradual degradation into smaller fractions or even monomers in
vivo, which can be subsequently metabolized by the body (Gutiérrez 2018b). This
biodegradability helps to design drug delivery systems with controllable and targetable drug release properties, as well as to reduce the possible side effects associated
with the accumulation of them.
Since polymers are composed of monomers linked by covalent bonds, therefore,
degradation of them requires the breaking of said bonds. Current knowledge about
X. Guo et al.