The process of applying relatively thin coatings around a substance which may
be solids, liquids, or even gases is called encapsulation. Based on the size of the
coated particles, the process may be microencapsulation or nanoencapsulation.
Encapsulation separates the encapsulated materials also known as the core materials
from the environment with the help of a coating material, usually a polymer. Thus,
encapsulation provides protection of the core material and it may also add certain
functionalities such as color for identification, masking of taste, or sustaining the
release of the core materials. As a result, micro- or nanoencapsulation has become
an indispensable technology in various industries including pharmaceuticals, cosmetics, nutraceuticals, and agriculture.
Encapsulation is one of the techniques that can be applied to enhance oral
bioavailability, solubility, dispersibility, and stability of bioactive compounds
(Beevers and Huang 2011; Ezhilarasi et al. 2013; Gomez-Estaca et al. 2015; Li
et al. 2015; Shaikh et al. 2009). Numerous methods have been applied in the
encapsulation of various natural bioactive compounds utilizing wide range of
coating materials such as lipids, natural, and synthetic polymers (Anirudhan and
Binusree 2016; Islam Shishir et al. 2018; Oehlke et al. 2017; Pinho et al. 2013;
Shao et al. 2011; Sharma et al. 2007; Young et al. 2005). The selection of the
coating materials is critical as the size, shape, and stability of the final encapsulated
product as well as the release characteristics of the core material is largely determined by the type and amount of the coating materials used (Dias et al. 2017).
20.2 Rationale for Encapsulation of Bioactive Compounds
Encapsulation of natural bioactive compounds into various nano- or
micro-platforms has the potential to resolve several drawbacks that are inherent to
these phytochemicals. This may range from improving their physicochemical
properties such as solubility and stability, to their pharmacokinetics such as
absorption and the overall bioavailability. Some of the advantages offered by
encapsulation of bioactive compounds can be summarized as follows:
(a) Enhanced bioavailability and therapeutic activity: Improvement in
bioavailability of poorly absorbable phytochemicals such as polyphenols has been
reported after their encapsulation into various systems such as solid lipid
nanoparticles (SLN), micelles, liposomes, and others (Aqil et al. 2013; Murugan
et al. 2009; Puligundla et al. 2017; Xie et al. 2011; Yang et al. 2008). This
enhancement in bioavailability can be manyfold, as at least ninefold increase in oral
bioavailability had been reported for poly(lactic-co-glycolic acid) (PLGA)
nanoencapsulation of curcumin (Shaikh et al. 2009), while 942.53% enhancement
in relative bioavailability was also reported for curcumin encapsulated in SLNs (Ji
et al. 2014).
(b) Stability: Most of the bioactive compounds from plants are susceptible to
light, heat, and pH changes developing unpleasant flavor or colors (Alborzi et al.
2012; Fang and Bhandari 2010; Prakash et al. 2018; Rezaei et al. 2019; Soukoulis
690
L. Pachuau et al.
be solids, liquids, or even gases is called encapsulation. Based on the size of the
coated particles, the process may be microencapsulation or nanoencapsulation.
Encapsulation separates the encapsulated materials also known as the core materials
from the environment with the help of a coating material, usually a polymer. Thus,
encapsulation provides protection of the core material and it may also add certain
functionalities such as color for identification, masking of taste, or sustaining the
release of the core materials. As a result, micro- or nanoencapsulation has become
an indispensable technology in various industries including pharmaceuticals, cosmetics, nutraceuticals, and agriculture.
Encapsulation is one of the techniques that can be applied to enhance oral
bioavailability, solubility, dispersibility, and stability of bioactive compounds
(Beevers and Huang 2011; Ezhilarasi et al. 2013; Gomez-Estaca et al. 2015; Li
et al. 2015; Shaikh et al. 2009). Numerous methods have been applied in the
encapsulation of various natural bioactive compounds utilizing wide range of
coating materials such as lipids, natural, and synthetic polymers (Anirudhan and
Binusree 2016; Islam Shishir et al. 2018; Oehlke et al. 2017; Pinho et al. 2013;
Shao et al. 2011; Sharma et al. 2007; Young et al. 2005). The selection of the
coating materials is critical as the size, shape, and stability of the final encapsulated
product as well as the release characteristics of the core material is largely determined by the type and amount of the coating materials used (Dias et al. 2017).
20.2 Rationale for Encapsulation of Bioactive Compounds
Encapsulation of natural bioactive compounds into various nano- or
micro-platforms has the potential to resolve several drawbacks that are inherent to
these phytochemicals. This may range from improving their physicochemical
properties such as solubility and stability, to their pharmacokinetics such as
absorption and the overall bioavailability. Some of the advantages offered by
encapsulation of bioactive compounds can be summarized as follows:
(a) Enhanced bioavailability and therapeutic activity: Improvement in
bioavailability of poorly absorbable phytochemicals such as polyphenols has been
reported after their encapsulation into various systems such as solid lipid
nanoparticles (SLN), micelles, liposomes, and others (Aqil et al. 2013; Murugan
et al. 2009; Puligundla et al. 2017; Xie et al. 2011; Yang et al. 2008). This
enhancement in bioavailability can be manyfold, as at least ninefold increase in oral
bioavailability had been reported for poly(lactic-co-glycolic acid) (PLGA)
nanoencapsulation of curcumin (Shaikh et al. 2009), while 942.53% enhancement
in relative bioavailability was also reported for curcumin encapsulated in SLNs (Ji
et al. 2014).
(b) Stability: Most of the bioactive compounds from plants are susceptible to
light, heat, and pH changes developing unpleasant flavor or colors (Alborzi et al.
2012; Fang and Bhandari 2010; Prakash et al. 2018; Rezaei et al. 2019; Soukoulis
690
L. Pachuau et al.