**1. Introduction**

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256 Application of Nanotechnology in Drug Delivery

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In the recent decades, polymers are widely used as biomaterials due to their favorable properties such as good biocompatibility, easy design and preparation, a variety of structures and interesting bio-mimetic character. Especially in the field of smart drug delivery, polymer played a significant role because it can deliver therapeutic agents directly into the intended site of action, with superior efficacy. The ideal requirements for designing nano-particulate delivery system are to effectively be controlled particle size, surface character; enhance permeation, flexibility, solubility and release of therapeutically active agents in order to attain the target and specific activity at a predetermined rate and time. The smart drug delivery systems have been successfully made by the advances in polymer science in the bio-nano‐ technology field. Recently, these advances have been found in various medical applications for nano-scale structures in smart drug delivery. The smart drug delivery systems should possess some important feature such as pre-scheduled rate, self controlled, targeted, predetermined time and monitor the delivery. The smart drug delivery system enhances the polymer nanoparticle better stage to their therapy regimen. They are drug carriers of natural, semi-synthetic, and synthetic polymeric nature at the nano-scale to micro-scale range. The polymeric particles are collectively named as spheres and capsules. The most of the polymeric nanoparticles with surfactants offer stability of various forms of active drugs and have useful to smart release properties. There are numerous biological applications have been reported for the nano-scale to micro-scale sized particles, such as site-targeted, controlled, and enhanced bioavailability of hydrophobic drugs [1-4]. Due to the nanoparticles size the drugs have been targeting into various applications, such as, various cancers targeting has been shown to be promising [5]. Moreover, polymeric particles proved their effectiveness in stabilizing and protecting the drug molecules such as proteins, peptides, or DNA molecules from various environmental hazards degradation [2-4, 6, 7]. So these polymers are affording the potential for various protein and gene delivery. Numerous methods had been available to fabricate

© 2014 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

nanoparticles; it depends on the physical and chemical properties of polymer and active ingredients. Most of the formulation techniques involve different mechanisms such as using organic solvents, temperature, ultra-sonication and mechanical agitation which can degrade the pharmaceutical active ingredients. So the nano-particulate system can be developed to consider the formulation methodology should not damage the active pharmaceutical ingre‐ dients. There are numerous biodegradable and biocompatible polymers with different physicochemical characters are offered to prepare smart nanoparticles, those polymeric nanocarriers can be natural or semi-synthetic or synthetic. Those nanoparticles can enhance the systemic circulation half-life and minimize unwanted internalization and prevents the denaturation of the therapeutically active moiety and could use to deliver the target agents. Several polymer systems are approved by the U.S. Food and Drug Administration (FDA) for human use. It is the belief that when inventions in fabrication can catch up with those in materials, design and development of drug delivery system can enter a new generation of enhancing clinical healthcare.

transformation of nanoparticles, which the particles are well-controlled formulated. This chapter will be followed by a more detailed novel drug delivery system development from a polymeric material viewpoint and their various bio-applications will be covered without

Polymer Nanoparticles for Smart Drug Delivery

http://dx.doi.org/10.5772/58422

259

Over a decade, investigators have appreciated the enrichment of potential uses of bionanotechnology in offering huge advancements in novel drug delivery and targeting. The novel drug delivery platform that provides diminishes toxicity and enhances therapeutic efficacy gives most possible benefits to clinical levels. In approaches to drug delivery systems the route of administration is one of the crucial roles of drug targeting. These nanoparticles can be used for various routes, including oral, nasal, transdermal, parenterals, pulmonary, ocular, etc. Nonetheless, the oral route is most convenient, preferred, and in several cases, also its cost-effective, but it does not cross easily some biological barrier; also easily degraded by various body fluids, then rapid hepatic clearance and other organs. So the drug delivery systems focus on overcoming the various membrane barriers, such as the blood brain barrier, tight junction barrier, to achieve the effective drug target and enhance the efficacy. To find an alternative and satisfiable route of administration for the effective drug delivery system should overcome the digestive tract problems, where the degradation could take place via acidhydrolysis, enzymatic degradation and bacterial fermentation in the alimentary canal. This chapter will cover the more detailed novel route of administration and development from a polymeric material viewpoint and their brief discussion will be covered without attempting

attempting to all the work that has been done in this field.

to all the work that has been done in this field.

**2. General methods for polymeric nanoparticles preparation**

Recently, various kinds of polymers are used to prepare the polymeric nanoparticles, among this all polymer biodegradable polymers and their co-polymers such as di-block, tri-block, multi-block or radial block copolymer structures have been generally used to prepare poly‐ meric nanoparticles and to encapsulate the active ingredients. These multi-functionalized polymeric nano-carriers include micelles, capsules, platelets, fibers, spheroids colloids, dendrimers, core-shells, nanoparticle incorporated polymer matrixes, etc. The first polymeric nanoparticles were developed between the year of 1960 to 1970 for the therapeutic application, and this were Micelles[10-12].The micelles are formed by polymerisation methods, commonly the formation of polymer nano-carriers during the polymerization of monomers [13-16]. Then the various advanced polymerization techniques have been developed for the preparation polymeric based nanoparticles, and the nanoparticles were stabilised using various surfactants [1, 9]. The stabilised drug loaded nanoparticles consist of drug and non-toxic biocompatible polymer with stabilizing agents, the biocompatible polymer is either biodegradable or nonbiodegradable. Numerous techniques are available for the preparation of the polymeric nanoparticles and mainly top-down and bottom up processes. The polymer nanoparticle drug carriers can be further categorized into nano/micro-capsules and nano/micro-spheres depends on the size and structure [1, 9, 17-19]. The fine particles are 100 - 2,500 nm and ultrafine particles are 1 to100 nm in size, and are collectively known as nanoparticles. 50 to 300 nm sized

The most recent advances in the uses of carriers for sustained and targeted delivery, micro and nano fabricated self-regulated devices [8], bio-recognizable systems; micro-needles for transdermal drug delivery have shown the flexibility and enhanced permeability of these polymeric materials. Ultimately the goal in smart drug delivery is the emergence of a micro and nano-fabricated therapeutic drug release device with the capacity to enough hold and release of various active agents on demand. In modern system the micro-electro-mechanical systems give a distinctive possibility to produce micro-fabricated biomedical devices for different intentions, from implantable systems to lab-on-a-chip systems. The constant and prolonged drug release micro-fabricated systems have the several benefits, such as many active ingredients could be stored in an nano form within the system and sustainably released, the drug release is initiated by the dissolution and disintegration of outer membrane barrier by an mechanical/electric stimuli, the most potential drugs could be released more specifically with this technique, the complex drug release system such as simultaneous stable and periodically could be attained for local therapy by the micro-fabricated system; it can be achieved in high or low dose of drugs at the targeted site and increase the stability of drugs by the membrane barrier for preventing water diffusion into the reservoirs [9]. Owing to the advanced scientific sophistication of the controlled drug release system that has been achieved till now, or that are in dynamic progress, this delivery model can be categorized into various classes. The controlled drug delivery systems can be categorize four main mode of drug delivery, such as (1) rate-programmed drug delivery, where drug diffusion from the system has follow a specific release rate profile, (ii) activation-modulated drug delivery, where the drug release is induced by various factors such as physical, chemical electrical or biochemical modules, (iii) feedback-regulated drug delivery, where the rate of release is determined by biochemical substance (triggering agent) concentrations, it is dependent on the concentration exhibit in the target and (iv) site-targeting drug delivery systems, this is a complex process that consists of multiple steps of diffusion rate and partitioning for the rate of drug release is regulated by the specific targeting moiety, solubilizer and drug moiety. This chapter will brief discussion on recent innovative nano-fabrication methods for novel drug delivery system. Also, highlights some of these new technologies and consider their possibility ongoing clinical transformation of nanoparticles, which the particles are well-controlled formulated. This chapter will be followed by a more detailed novel drug delivery system development from a polymeric material viewpoint and their various bio-applications will be covered without attempting to all the work that has been done in this field.

nanoparticles; it depends on the physical and chemical properties of polymer and active ingredients. Most of the formulation techniques involve different mechanisms such as using organic solvents, temperature, ultra-sonication and mechanical agitation which can degrade the pharmaceutical active ingredients. So the nano-particulate system can be developed to consider the formulation methodology should not damage the active pharmaceutical ingre‐ dients. There are numerous biodegradable and biocompatible polymers with different physicochemical characters are offered to prepare smart nanoparticles, those polymeric nanocarriers can be natural or semi-synthetic or synthetic. Those nanoparticles can enhance the systemic circulation half-life and minimize unwanted internalization and prevents the denaturation of the therapeutically active moiety and could use to deliver the target agents. Several polymer systems are approved by the U.S. Food and Drug Administration (FDA) for human use. It is the belief that when inventions in fabrication can catch up with those in materials, design and development of drug delivery system can enter a new generation of

The most recent advances in the uses of carriers for sustained and targeted delivery, micro and nano fabricated self-regulated devices [8], bio-recognizable systems; micro-needles for transdermal drug delivery have shown the flexibility and enhanced permeability of these polymeric materials. Ultimately the goal in smart drug delivery is the emergence of a micro and nano-fabricated therapeutic drug release device with the capacity to enough hold and release of various active agents on demand. In modern system the micro-electro-mechanical systems give a distinctive possibility to produce micro-fabricated biomedical devices for different intentions, from implantable systems to lab-on-a-chip systems. The constant and prolonged drug release micro-fabricated systems have the several benefits, such as many active ingredients could be stored in an nano form within the system and sustainably released, the drug release is initiated by the dissolution and disintegration of outer membrane barrier by an mechanical/electric stimuli, the most potential drugs could be released more specifically with this technique, the complex drug release system such as simultaneous stable and periodically could be attained for local therapy by the micro-fabricated system; it can be achieved in high or low dose of drugs at the targeted site and increase the stability of drugs by the membrane barrier for preventing water diffusion into the reservoirs [9]. Owing to the advanced scientific sophistication of the controlled drug release system that has been achieved till now, or that are in dynamic progress, this delivery model can be categorized into various classes. The controlled drug delivery systems can be categorize four main mode of drug delivery, such as (1) rate-programmed drug delivery, where drug diffusion from the system has follow a specific release rate profile, (ii) activation-modulated drug delivery, where the drug release is induced by various factors such as physical, chemical electrical or biochemical modules, (iii) feedback-regulated drug delivery, where the rate of release is determined by biochemical substance (triggering agent) concentrations, it is dependent on the concentration exhibit in the target and (iv) site-targeting drug delivery systems, this is a complex process that consists of multiple steps of diffusion rate and partitioning for the rate of drug release is regulated by the specific targeting moiety, solubilizer and drug moiety. This chapter will brief discussion on recent innovative nano-fabrication methods for novel drug delivery system. Also, highlights some of these new technologies and consider their possibility ongoing clinical

enhancing clinical healthcare.

258 Application of Nanotechnology in Drug Delivery

Over a decade, investigators have appreciated the enrichment of potential uses of bionanotechnology in offering huge advancements in novel drug delivery and targeting. The novel drug delivery platform that provides diminishes toxicity and enhances therapeutic efficacy gives most possible benefits to clinical levels. In approaches to drug delivery systems the route of administration is one of the crucial roles of drug targeting. These nanoparticles can be used for various routes, including oral, nasal, transdermal, parenterals, pulmonary, ocular, etc. Nonetheless, the oral route is most convenient, preferred, and in several cases, also its cost-effective, but it does not cross easily some biological barrier; also easily degraded by various body fluids, then rapid hepatic clearance and other organs. So the drug delivery systems focus on overcoming the various membrane barriers, such as the blood brain barrier, tight junction barrier, to achieve the effective drug target and enhance the efficacy. To find an alternative and satisfiable route of administration for the effective drug delivery system should overcome the digestive tract problems, where the degradation could take place via acidhydrolysis, enzymatic degradation and bacterial fermentation in the alimentary canal. This chapter will cover the more detailed novel route of administration and development from a polymeric material viewpoint and their brief discussion will be covered without attempting to all the work that has been done in this field.
