The compounds of interest are very beneficial for drug delivery applications because of their ability to control drug release and their protection properties [75]. Currently, stimuli-sensitive nanoparticles which affected by the changes in pH, temperature and magnetic fields gained great concern [76-79].
The term “polymeric nanoparticle” encompasses nanospheres and nanocapsules.
Nanospheres are defined as a polymeric matrix in which the drug is homogeneously dispersed (typically as a solid solution in polymer) and nanocapsules are described as a polymeric membrane that surrounds the drug in the matrix core[80] (either as a solid solution or a solution in oil).
Advantages of polymeric nanoparticles include: [81, 82]
(1) improve the stability of any volatile pharmaceutical agents, simply and economically fabricated in large quantities by a huge number of methods, (2) they present a significant improvement over conventional oral and intravenous routes of administration in terms of efficiency and effectiveness, (3) delivers a higher concentration of pharmaceutical agent to the required location, (4) the selection of polymer and the capability of modifying drug release from polymeric nanoparticles have made them typical choice for cancer therapy, delivery of vaccines, contraceptives and delivery of targeted antibiotics and (5) Polymeric nanoparticles can be easily included into other activities related to drug delivery, such as tissue engineering.
In nanoparticles formulations wide variety of polymers can be used according to the nature of drug and usage. (i.e.) Biodegradable polymers for short term therapy (e.g. Chemotherapeutic agents) and non-biodegradable polymers for long term therapy (e.g. Vaccines) [83].
The PNPs are obtained from synthetic polymers, such as poly- Ɛ-caprolactone [84], poly-acrylamide [85] and polyacrylate [86], or natural polymers, e.g., Albumin [87], DNA[88], chitosan [88, 89] and gelatin [90].Based on in vivo behavior, PNPs may be classified as biodegradable, i.e., Poly (L-lactide) (PLA) [91], polyglycolide (PGA) [92], and non biodegradable, e.g. Polyurethane [93].
The drug release along the GIT can be controlled using pH-sensitive materials, in which the drug is released particularly in the small intestine near the absorption site. PH-dependent materials, which are insoluble in the acidic medium of the stomach, but dissolve in the intestinal fluid, are called e
