Biol. Pharm. Bull. 29(9) 1790—1798 (2006)

In recent years, the interest in sub-micron systems (i.e. nanosystems) in pharmacy has surged. This is in part due to the advantages these systems may provide over existing systems. Designing drug delivery system is challenging in terms of targeting the drug to specific sites. Certain chemicals or therapeutic agents that show success in cell culture fail to produce the same effect in the human body because of the limitation to target the designated area, as a result, high concentrations are given to patients resulting in more intense side effects. This case is similar to biopharmaceuticals and biotechnological drugs such as recombinant proteins, vaccines, antibiotics and genes, etc. However, many of them require special formulation technologies to overcome drug-associated problems such as poor solubility, drug instability in biological milieu (i.e. short half life), poor bioavailability, and potentially strong side effects that require drug enrichment at the site of action. The high-protein binding property of certain drugs hinders their passage into the brain and other organs. Suitable drug delivery systems are crucial and this is supported by a recent report stating that pharmaceuticals account for approximately $65 billion in drug revenue every year. Poor bioavailability far too often results in not only higher patient costs and inefficient treatment, but also, more importantly, increased risks of toxicity or even death. 1.1. Need of Nanocarrier Nanotechnology is a novel area of science that provides, with a new hope, the tools and technology to work at atomic, molecular and supramolecular levels leading to creation of devices and delivery systems with fundamentally new properties and functions. Nanocarriers offers a number of advantages making it an ideal drug delivery vehicle (Fig. 1). · Nanocarriers can better deliver drugs to tiny areas within the body. · It represents engineering of particles, which are smaller than 100 nanometers. · Nanotechnology is so complementary to biotechnology that promises to bridge the gaps between ‘the structure’ and ‘the function’ of biomolecules as well as between ‘human physiology’ and ‘pathophysiology’. · This allows the engineering of products on a comparable scale to nature such as biologicals like proteins, DNA and viruses, which are of the order of 10’s of nanometers in size and cells and cellular assemblies of the order of 1000’s of nanometers. · Sophisticated techniques and tools have enabled the better characterization and manipulation of material at nanoscale level to elucidate nanoscale phenomenon leading to generation of new era of nanostructure-mediated drug delivery. Engineering on this scale enables researchers to exercise exquisite and previously unthinkable control over the physical attributes of polymers and other biomaterials. · It is poised to help alleviate the problems of drug delivery with the development of nanostructured delivery methods in combination with utilization of principles and techniques of biotechnology to manipulate molecular, genetic, and cellular processes leading to creation of a new interdisciplinary approach. · It involves overlap of biotech, nanotech, and information technology, might result in many important applications in life sciences including areas of gene therapy, drug delivery, imaging, biomarkers, biosensors and novel drug discovery techniques. · It also offers an attractive solution for transformation of biosystems, and provides a broad platform in several areas of bioscience. · Nanocarriers overcome the resistance offered by the physiological barriers in the body because efficient delivery of drug to various parts of the body is directly affected by particle size. · Nanocarriers aid in efficient drug delivery to improve aqueous solubility of poorly soluble drugs that enhance bioavailability for timed release of drug molecules, and precise drug targeting. · The surface properties of nanocarriers can be modified for targeted drug delivery for e.g. small molecules, proteins, peptides, and nucleic acids loaded nanoparticles are not recognized by immune system and efficiently targeted to particular tissue types. · Targeted nano drug carriers reduce drug toxicity and provide more efficient drug distribution. · Nanocarriers holds promise to deliver biotech drugs over various anatomic extremities of body such as blood brain 1790 Vol. 29, No. 9