Pharmaceutical Manufacturing Handbook: Production and

1290 PHARMACEUTICAL NANOSYSTEMS
7.3.1
DEFINITION
Nanotechnology is an enabling technology and one which is generally manifest at
the primary level in the form of nanomaterials. The defi nition of nanotechnology
therefore focuses on materials and how manipulation at the nanoscale leads to novel
properties and therefore potentially new uses. The pharmaceutical industry has yet
to adopt strict guidelines for what falls under the remit of nanotechnology, with
numerous defi nitions in existence. For the purpose of this chapter, the current U.S.
Food and Drug Administration (FDA) defi nition for nanotechnology as applied to
pharmaceuticals is deemed most appropriate. The FDA describes nanotechnology
as technology that includes the following [1] :
1. Research and technology development or products regulated by the FDA that
are at the atomic, molecular or macromolecular levels and where at least one
dimension that affects the functional behavior of the product is in the length
scale range of approximately 1 – 100 nm
2. Creating and using structures, devices, and systems that have novel properties
and functions because of their small and/or intermediate size
3. Ability to control or manipulate at the atomic scale
Nanotechnology is therefore essentially about understanding and manipulating
materials at the atomic, molecular, and macromolecular level in a way that imparts
properties to the material that would otherwise not exist either as individual atoms
or as bulk processed macroscopic systems.
Properties that can be exploited to provide novel and unique properties to materials
include surface and quantum effects, for example, van der Waals forces; electrostatic
interaction; ionic, covalent and hydrogen bonding; and quantum confi nement.
Additionally nonconventional means of molecular assembly and atomic manipulation
can lead to novel material properties. Control and exploitation of these effects
can lead to new and useful changes to the thermal, magnetic, electrical, optical and
mechanical, and biological and physicochemical properties of materials.
7.3.1.1
Top - Down and Bottom - Up Approaches to Nanotechnology
There are generally two approaches to nanotechnology, the top - down and bottom -
up approaches. As the names suggest, the top - down approach utilizes ultraprecision
machining and nanolithographic techniques among others to achieve very high
defi nition structures with nanolevel accuracy, usually either by removing material
from the surface of a larger structure until the desired structure with desired features
is achieved or through deposition of material with almost atomic - scale precision
and control. The bottom - up approach involves the assembly of atoms, molecules,
or nanoscale components to assemble a larger structure within the nanoscale range.
There are numerous methods by which this can be achieved, including conventional
bulk chemical processing methods and exploitation of chemical and biological self -
assembly techniques. The pharmaceutical industry is primarily involved in the application
of nanomaterials rather than the discovery and development of new materials,
though as this chapter will indicate, there are often areas of overlap between what
is a new material and a construct of a novel material.