increase the oral bioavailability of poorly soluble alkaloid, vinpocetine by about 4to 4.9-folds (Song et al. 2015).
20.3.2.6 Hydrogels
Hydrogels are hydrophilic three-dimensional polymer networks which can take up
large amount of water. They are biodegradable and the three-dimensional network
of the hydrogel disintegrates into non-toxic materials with excellent biocompatibility (Akhtar et al. 2016). Hydrogels are prepared from wide ranges of natural and
synthetic polymers and can be presented in the various physical forms such as
beads, microparticles, nanoparticles, and films and they have become one of the
promising encapsulating systems to provide protection to sensitive phytochemicals
and for their controlled delivery (Abaee et al. 2017; Gomez-Mascaraque et al.
2016a). The advantages hydrogels offer in encapsulation of bioactive compounds
include the following:
(i) Enhancing stability and bioacessibility of sensitive, poorly aqueous-soluble
bioactive molecules (Gomez-Mascaraque et al. 2016a; Han et al. 2020;
Zhang et al. 2016).
(ii) pH-dependent and controlled release of bioactive compounds (Bourbon et al.
2016; Lopez Cordoba et al. 2013; Rutz et al. 2013).
(iii) Efficient encapsulation of both hydrophilic and hydrophobic bioactive
compounds (Bourbon et al. 2016).
(iv) Enhancing bioactivity (Chan et al. 2010).
(v) Improving bioavailability (McClements 2017).
(vi) High drug-loading capacity due to their large spacing within the polymeric
network (Teng et al. 2015).
Various hybrid hydrogel systems such as emulsion hydrogels, organogels and
bigels have also been evaluated for encapsulation of bioactive compounds.
Encapsulation of bioactive compounds within these networks can improve their
stability, solubility and dispersibility thereby improving their overall bioavailability
(Mao et al. 2019). Suitable functionalities such as responsiveness to pH, temperature, enzymes etc. can also be imparted to these hybrid hydrogels to provide the
desired release characteristics of the formulation (McClements 2017). In emulsion
(O/W) gel systems, the continuous aqueous phase gets solidified or gelled to provide structural integrity and flexibility to the whole system. As a result, it has wide
application in functional food industry. Bioactive compounds such as curcumin
(Geremias-Andrade et al. 2017), quercetin (Chen et al. 2018), a-tocopherol (Freire
et al. 2018) have been delivered through emulsion gel systems with improved
stability, bioaccessibility and controlled release. In addition, the structural state of
emulsion hydrogels also allows them to be used as an efficient fat-replacement in
various food products without affecting their sensory characteristics thereby promoting health benefits to consumers (Pintado et al. 2015, 2016).
702
L. Pachuau et al.
20.3.2.6 Hydrogels
Hydrogels are hydrophilic three-dimensional polymer networks which can take up
large amount of water. They are biodegradable and the three-dimensional network
of the hydrogel disintegrates into non-toxic materials with excellent biocompatibility (Akhtar et al. 2016). Hydrogels are prepared from wide ranges of natural and
synthetic polymers and can be presented in the various physical forms such as
beads, microparticles, nanoparticles, and films and they have become one of the
promising encapsulating systems to provide protection to sensitive phytochemicals
and for their controlled delivery (Abaee et al. 2017; Gomez-Mascaraque et al.
2016a). The advantages hydrogels offer in encapsulation of bioactive compounds
include the following:
(i) Enhancing stability and bioacessibility of sensitive, poorly aqueous-soluble
bioactive molecules (Gomez-Mascaraque et al. 2016a; Han et al. 2020;
Zhang et al. 2016).
(ii) pH-dependent and controlled release of bioactive compounds (Bourbon et al.
2016; Lopez Cordoba et al. 2013; Rutz et al. 2013).
(iii) Efficient encapsulation of both hydrophilic and hydrophobic bioactive
compounds (Bourbon et al. 2016).
(iv) Enhancing bioactivity (Chan et al. 2010).
(v) Improving bioavailability (McClements 2017).
(vi) High drug-loading capacity due to their large spacing within the polymeric
network (Teng et al. 2015).
Various hybrid hydrogel systems such as emulsion hydrogels, organogels and
bigels have also been evaluated for encapsulation of bioactive compounds.
Encapsulation of bioactive compounds within these networks can improve their
stability, solubility and dispersibility thereby improving their overall bioavailability
(Mao et al. 2019). Suitable functionalities such as responsiveness to pH, temperature, enzymes etc. can also be imparted to these hybrid hydrogels to provide the
desired release characteristics of the formulation (McClements 2017). In emulsion
(O/W) gel systems, the continuous aqueous phase gets solidified or gelled to provide structural integrity and flexibility to the whole system. As a result, it has wide
application in functional food industry. Bioactive compounds such as curcumin
(Geremias-Andrade et al. 2017), quercetin (Chen et al. 2018), a-tocopherol (Freire
et al. 2018) have been delivered through emulsion gel systems with improved
stability, bioaccessibility and controlled release. In addition, the structural state of
emulsion hydrogels also allows them to be used as an efficient fat-replacement in
various food products without affecting their sensory characteristics thereby promoting health benefits to consumers (Pintado et al. 2015, 2016).
702
L. Pachuau et al.