**Current Status and Future Scope for Nanomaterials in Drug Delivery**

Biswajit Mukherjee, Niladri Shekhar Dey, Ruma Maji, Priyanka Bhowmik, Pranab Jyoti Das and Paramita Paul

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/58450

## **1. Introduction**

[35] Adams DJ. The Valley of Death in anticancer drug development: a reassessment.

Trends in Pharmacological Sciences. 2012;33(4):173-80.

524 Application of Nanotechnology in Drug Delivery

Nanotechnology is a revolutionary field of micro manufacturing involving physical and chemical changes to produce nano-sized materials. The word "nano" is a Latin word meaning "dwarf". Mathematically a nanometer is equal to one thousand millionth of a meter [1]. A nanomaterial consists of aggregated as well as unbound particles. Nanotechnology in scientific terms is defined as the science which deals with processes that occur at molecular and atomic level or at nanolength size. It involves designing, synthesis and characterization of material structure by controlling the shapes and sizes at nano scale. The conversion of a particle to nano scale size changes the properties of the material such as increase in surface area, dominance of quantum effects often associated with minute sizes, higher surface area to volume ratio etc. and varies material's magnetic, thermal and electrical property. For example, copper which is opaque at macro scale becomes transparent at nano scale. Similarly the properties of gold at nanoscale causes change in melting point from 200°C to 1068°C and colour changes from yellow to blue to violet along with the change in its catalytic property [2]. Nanoparticles are persistent in nature as well. Functional proteins may be classified as nanoparticles. Some biological system consists of nanoparticles which are devoted to locomotory function. The colours on butterfly's wings are due to light being bounced off nanoscale layers in the structure of the wings. The red and yellow colours seen at sunset are also due to nanoparticles [3]. Super paramagnetic iron oxide less than 50 μm are used for imaging of organs. They can be even used for treating complicated brain disorder bio-imaging at nano scale size [9].

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Indian craftsman and artisan used nanotechnology for designing weapons in early times. The first observation and size measurement of nanoparticle were carried out using an ultra microscope by Richard Zsigmondy in 1902. The term nanotechnology was first time used by a researcher named Norio Taniguchi in University of Tokyo in 1974. In 1980 the inventions of two atoms further advanced the field of Nanotechnology. In 1985 fullerene C60 was discovered by Kroto's and Smalley's research team. In 1991 carbon tubes were discovered by Saumio lijima and by 2000 National Nanotechnology Initiative (NNI), The United States was launched which paved the way for future development in nanotechnology [2].

very low so that they can be used to target the specific diseased tissue in a safe concentra‐ tion [7]. They need protecting drug from enzymatic and hydrolytic degradation in the gastrointestinal tract and help in bypassing the "first-pass" metabolism in the liver. They generally remain in the circulation for longer time especially those coated with hydrophil‐ ic polymers and hence suitable for enhancing the efficacy of drugs with short half-lives and can be used to monitor drug as sustained release formulation as well as for delivering DNA [8]. The dissolution rate of drug is enhanced, onset of therapeutic action is increased, and the dose is reduced. The premature loss of drug through rapid clearance and metabolism

Current Status and Future Scope for Nanomaterials in Drug Delivery

http://dx.doi.org/10.5772/58450

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Nanoscale drug delivery systems such as nanoparticles, nanoliposomes, dendrimers, fullerence, nanopores, nanotubes, nanoshells, quantum dots, nanocapsule, nanosphere, nanovaccines, nanocrystals etc. are believed to have potentials to revolutionize drug delivery systems. Further nanomaterials on chips, nano robotics, and magnetic nanoparti‐ cles attached to specific antibody, nanosize empty virus capsids and magnetic immunoas‐ say are new dimensions of their use in drug delivery. Thus nanomaterials can be used for strategic development of new drug delivery systems and reformulating existing drugs to enhance the effectiveness, patent protection, patient-compliance, safety of drugs and

Nanoparticles are submicron-sized polymeric colloidal particles with therapeutic agents of interest encapsulated or dispersed within their polymeric matrix or adsorbed or conjugated onto the surface. Commonly used synthetic polymers to prepare nanoparticles for drug delivery are generally biodegradable [10]. Nanoparticles may also be composed of or transport a variety of substances such as silica, gold or other heavy metals, medicaments, quantum dots, nanocrystals, quantum rods and various contrast agents [11]. Nanoparticle systems offer major improvements in therapeutics through site specificity, their ability to escape from multi-drug resistance and the efficient delivery of an agent. They can be used for active drug targeting

Solid lipid nanoparticles (SLNs) refer to as lipospheres or solid lipid nanospheres, or particles

than 1000 nm [12]. They can be formed from a range of lipids, including mono-, di- and triglycerides, fatty acids, waxes and combinations there of. SLNs must be stabilized by surfactants to form administrable emulsions. SLNs form a strongly lipophilic matrix into which drugs can be loaded for subsequent release. SLNs have been investigated for the delivery of

Polymer-based nanoparticles have been extensively investigated as drug nanocarriers. The most widely researched synthetic polymers include polylactide (PLA), poly (D,L-lactide-co-

C) and have a diameter less

can also be prevented [6]. They also increase retention due to bio-adhesion.

decreasing the cost of health care [9].

**3.1. Nanoparticles**

**3. Various nanoscale drug delivery systems**

attaching ligand such as antibody on their surface (Figure 1).

and are generally solid at human physiological temperature (37o

various cancer treatments like colon cancer, breast cancer [13].

Nanotechnology may be considered as one of the main propellants for technological, econom‐ ical change as industrial competeition. Nanotechnology has integrated various disciplines including biomedicine, engineering and technology. Nanotechnology is being used for improving the existing products and to create new products. The strength can be varied accordingly with the requirements of engineering. It can be used to make the water cleaner by remediation to remove its pollutant. It has helped to clean the environment by removing pollutants and has generated cleaner and cheaper energy. It has improved the healthcare system by introducing new devices for diagnosis, monitoring, treatment of diseases and drugdelivery [1].

Nanomaterials have wide applications in pharmaceutical sciences and technology. Few other predominant areas of use of nanotechnology are in drug delivery, and as diagnostic imaging and biosensor. These devices of nanoscale size are popularly known as nanomedicine. Thus nanomedicines are sub-micron size materials (<1μm) which are used for treatment, monitoring and diagnostic purposses. In the present chapter we will discuss on the current status and future strategies of nanosize drug delivery systems.
