of the final formulation. Besides this, they facilitate the regulation of pharmacodynamic and pharmacokinetic properties of the drug in the physiological system. As
per the conventional hypothesis, excipients used in the pharmaceutical preparations
do not have a prime role in the treatment of disease and are thought to be inert as
well. Till date several polymers have been used as excipients for the development of
polymer-based drug delivery system with the aim of targeted delivery of the active
therapeutics to the specific tissues (Ulbrich et al. 2016). Polymers can play a vital
role in disease management as well as they can also modulate the behaviour of the
drug in the physiochemical system. Although significant research has been done to
investigate the mechanistic behaviour of these polymers when used alone or as a
polymer-drug conjugate for the purpose of drug delivery. However, evaluation of the
physicochemical properties of the polymer prior to pharmaceutical application is a
task of priority (Singh and Pai 2015). A non-toxic, biocompatible and biodegradable
polymer is always a need for a biologically safe and effective pharmaceutical dosage
form. In recent years, demand of natural polymers has taken a quantum leap in
pharmaceutical, food and cosmetic industries than its synthetic counterpart (Zia et al.
2017). Synthetic polymers are used for drug delivery and development of biomedical
devices and implants. Though synthetic polymers exhibit high chemical, physical
and mechanical stability as well as flexibility to bind with diverse range of therapeutics, bio-incompatibility and cellular toxicity illustrated by them are always a
concern for drug delivery purpose (Nair and Laurencin 2007). Natural polymers
such as polysaccharides and proteins have been extensively used to develop
numerous biomedicines as they possess mighty biocompatible, biodegradable and
therapeutic properties. Moreover, natural polymers are more also easily assessable
and lower in cost compared to their synthetic counterparts (Li et al. 2015). These
natural polymers based drug delivery systems possess several advantages such as
high drug pay load, presence of diverse surface functional groups for drug binding
and low toxicity (O’Elzoghby et al. 2016).
11.1.1 Natural Gums
Gums are complex hydrocolloid biopolymers composed of polysaccharide consisting of one or more monosaccharides or their derivatives linked with chemical
linkages (Prajapati et al. 2013a, b). Natural gums can be classified on the basis of
their origin, e.g. marine origin (alginic acid, agar and carrageenans), animal origin
(chitin), microbial origin (gellan gum, xanthum gum and lentinan) and plant origin
(gum tragacanth, guar gum and cellulose) (Prajapati et al. 2013a, b; Choudhary and
Pawar 2014). Natural gums produced by higher plants are consequence of injury or
can be obtained from exudates of different parts of the plant. Easy availability,
non-toxicity, cost effectiveness and biocompatibility are some of the advantages of
natural gums which makes them a better alternative than their synthetic counterparts
380
P. Mishra et al.
per the conventional hypothesis, excipients used in the pharmaceutical preparations
do not have a prime role in the treatment of disease and are thought to be inert as
well. Till date several polymers have been used as excipients for the development of
polymer-based drug delivery system with the aim of targeted delivery of the active
therapeutics to the specific tissues (Ulbrich et al. 2016). Polymers can play a vital
role in disease management as well as they can also modulate the behaviour of the
drug in the physiochemical system. Although significant research has been done to
investigate the mechanistic behaviour of these polymers when used alone or as a
polymer-drug conjugate for the purpose of drug delivery. However, evaluation of the
physicochemical properties of the polymer prior to pharmaceutical application is a
task of priority (Singh and Pai 2015). A non-toxic, biocompatible and biodegradable
polymer is always a need for a biologically safe and effective pharmaceutical dosage
form. In recent years, demand of natural polymers has taken a quantum leap in
pharmaceutical, food and cosmetic industries than its synthetic counterpart (Zia et al.
2017). Synthetic polymers are used for drug delivery and development of biomedical
devices and implants. Though synthetic polymers exhibit high chemical, physical
and mechanical stability as well as flexibility to bind with diverse range of therapeutics, bio-incompatibility and cellular toxicity illustrated by them are always a
concern for drug delivery purpose (Nair and Laurencin 2007). Natural polymers
such as polysaccharides and proteins have been extensively used to develop
numerous biomedicines as they possess mighty biocompatible, biodegradable and
therapeutic properties. Moreover, natural polymers are more also easily assessable
and lower in cost compared to their synthetic counterparts (Li et al. 2015). These
natural polymers based drug delivery systems possess several advantages such as
high drug pay load, presence of diverse surface functional groups for drug binding
and low toxicity (O’Elzoghby et al. 2016).
11.1.1 Natural Gums
Gums are complex hydrocolloid biopolymers composed of polysaccharide consisting of one or more monosaccharides or their derivatives linked with chemical
linkages (Prajapati et al. 2013a, b). Natural gums can be classified on the basis of
their origin, e.g. marine origin (alginic acid, agar and carrageenans), animal origin
(chitin), microbial origin (gellan gum, xanthum gum and lentinan) and plant origin
(gum tragacanth, guar gum and cellulose) (Prajapati et al. 2013a, b; Choudhary and
Pawar 2014). Natural gums produced by higher plants are consequence of injury or
can be obtained from exudates of different parts of the plant. Easy availability,
non-toxicity, cost effectiveness and biocompatibility are some of the advantages of
natural gums which makes them a better alternative than their synthetic counterparts
380
P. Mishra et al.