Pharmaceutical Manufacturing Handbook: Production and

1252 NANOTECHNOLOGY IN PHARMACEUTICAL MANUFACTURING
of dendrimers or conjugated with them on the high reactive surfaces [23] . The fi rst
fullerene discovered was the buckyball, also known as buckminsterfullerene. It was
discovered by Smalley, Curl, and Kroto in 1985 [24] , who shared a Nobel Prize in
1996 for the discovery. Buckyball is roughly spherical cages of 60 carbon atoms
(C 60 ) arranged in interlocking hexagons and pentagons, like the patches on a soccer
ball. Fullerenes have attracted considerable research interest, partly because of
their unique structures and further because, once suitably dissolved, they display a
diverse range of biological activity [25] . Quantum dots (QDs) are semiconductor
nanocrystals commonly consisting of CdSe or ZnS. Besides their utilization as
electronic materials, QDs have recently been applied to biomedical areas after
modifi cation. The new generations of QDs have far - reaching potential for the study
of intracellular processes at the single - molecule level, high - resolution cellular
imaging, long - term in vivo observation of cell traffi cking, tumor targeting, and
diagnostics [26] .
Although many types of nanomaterials are created continually, the most important
and basic issues are nanoscale effects and the subsequent particular functions.
Nanomaterials with varied shapes and components provide different platforms to
achieve more functions. In the area of pharmaceutical manufacturing, people focus
on the drug delivery function of nanomaterials. Furthermore, the rapid development
of modern medicine has led to the belief that traditional drug dosage forms
such as tablets, capsules, and injections may not treat some vital diseases well,
perhaps not at all. Some advanced techniques developed in other disciplines should
be considered to apply to medicine. Nanomaterials can load and deliver drugs in
vivo as well as display special properties such as high dispersion, adhesive property,
and site - specifi c distribution in vivo. Modifi ed nanomaterials further possess new
functions, for example, they may be thermally sensitive, pH sensitive, magnetically
sensitive, and ultrasound sensitive.
Nanotechnology has a great effect on pharmaceutical manufacturing. The unique
functions of nanomaterials promise considerable benefi t to pharmacotherapy over
traditional drug preparations. When drug - loaded nanomaterials go through the
gastrointestinal tract, high dispersion and adhesion can lead to tight contact of
nanomaterials with mucous membranes, enhancing drug absorption. Nanomaterials
have been applied in all routes of administration, including oral, injection (intravenous,
subcutaneous, intramuscular, intra - articular cavity, and other possible injection
sites), intranasal, pulmonary inhalation, conjunctiva, topical, and transdermal,
possibly showing various required effects. Some of the characteristics and pharmaceutical
applications of nanomaterials are given in Table 1 . More applications will
continue to be developed.
7.2.2.2
Manufacturing and Processing of Nanomaterials
When material dimensions reach the nanoscale, quantum mechanical and thermodynamic
properties that are insignifi cant in bulk materials dominate, causing these
nanomaterials to display new and interesting properties. The manufacturing and
processing of nanomaterials may become diffi cult due to the unique properties. The
very small size of nanomaterials produces a very large surface - to - volume ratio, that
is, a great number of molecules/atoms locate on surfaces. High surface energy leads
to nanomaterials easily agglomerating to diminish energy unless enough hindrance