FIP Congress 2006
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Carwen Wynne-Howells reports from a symposium organised
by the Board of Pharmaceutical Sciences
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 The World Congress of Pharmacy and Pharmaceutical Sciences,
the 66th International FIP Congress, was organised by the International
Pharmaceutical Federation in association with the Federal
Council of Pharmacy of Brazil.
It took place in Salvador da Bahia from August 26 to 31, 2006
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Nanotechnology: current and potential applications
in drug delivery systems
ARTICLE CONTENTS
Nanotechnology: current and potential applications in drug delivery systems
What is nanotechnology?
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Roger Williams: there are regulatory issues with nanotechnology products |
What is nanotechnology?
Introducing the session, Salomon Stavchansky,
professor of pharmaceutics at the University of Texas, informed
the audience that the US Percentage
Private Equities List is “a pretty good indicator of where
the big money is being invested”.
He added that nanotechnology
is now a key area for investors in the US and one of the most exciting
areas of technological development. So what exactly is it?
Nanotechnology involves science at the smallest level. Often referred
to as “molecular manufacturing” it involves the use
of tiny particles or amorphous powders linked to a drug substance
manipulated on an atom-by-atom or molecule-by-molecule basis to
attain the desired configuration, he explained. |
Roger Williams, executive vice-president and chief executive officer
of the US Pharmacopeia, provided a comprehensive overview of the current
applications of nanotechnology and explored its potential applications
in drug delivery systems.
He began by citing some of the wider applications of nanotechnology.
These include:
• Energy — nanocrystals are an ideal light harvester in photovoltaic
devices
• Personal care — sunscreens are making use of nanoparticles that
are effective at absorbing light, especially in the UV range
• Sports — tennis balls with a nanocomposite coating keep bouncing
for longer
• Clothing — embedded nanoparticles can be used to create
stain-repellent materials
• Motor cars — use of nanocomposites in car bumpers makes them
lighter and more resistant to denting and scratching
The opportunities for using nanotechnology in drug delivery systems
are huge, said Dr Williams. It can be used to enhance drug properties
such as solubility, rate of dissolution, oral bioavailability and targeting
ability.
It can also be used to enhance dose requirements by reducing
the level of dose administered, producing more convenient dosage forms
and improving the side effect profile.
Some examples of systems employing this technology are:
• Multicomponent systems consisting of carrier plus therapeutic agent
• Implantable microchip-based delivery systems that deliver different
drugs under controlled conditions
• Injectable delivery systems using transdermal microneedles
A wide range of carriers are now used in nanoscale multifunctional therapeutics
and these include dendrimers, fullerenes, quantum dots, nanoshells and
liposomes, he told the audience.
All have the potential to produce novel drug delivery systems, for example,
a quantum dot with antibody or receptor targeting plus a new therapeutic
agent.
A number of therapeutic agents have already been approved for use. For
example, Abraxane, the first nanoparticle-based injectable drug formulation
to be approved by the US Food and Drug Administration, contains albumin-bound
paclitaxel for the treatment of metastatic breast cancer.
A number of devices have also been approved and include an antimicrobial
wound dressing covered with nanocrystalline silver that rapidly kills
a broad spectrum of bacteria in as little as 30 minutes.
One of the major issues for the FDA is how to regulate these new products
because they may be classified in a number of ways as drugs, medical
devices, biotechnology products (or biologics), tissue engineering products,
vaccines, cosmetics or combination products.
Having explored some potential models, Dr Williams went on to outline
some of the regulatory considerations. All nanotechnology products are
reviewed in terms of characterisation, safety and environmental impact:
Characterisation
• The forms in which the particles are presented to the host, cells and
organelles
• Long- and short-term stability of nanomaterials
• How the characterisation and manufacturing procedures are assessed
for “personalised therapies”
Safety considerations
• Particle size and specific effects on activity, eg, once nanoparticles
enter tissues how long do they stay there?
• Route-specific issues, eg, if inhaled what is the local respiratory
toxicity?
• Whether the current methods used for measuring drug levels in blood
and tissues adequate for assessing levels of nanoparticles.
Environmental considerations
• Can nanoparticles be released into the atmosphere following human and
animal use?
• How would you identify and quantify this?
• What is the potential impact on other species, eg, fish, plants, micro-organisms?
Currently there are no testing requirements that are specific to nanotechnology
products and the FDA currently takes the view that its range of tests
is sufficient. However, if research identifies toxicological risks that
are unique to nanomaterials additional testing may be required. With
this in mind the FDA has established a group to consider toxicity issues.
Dr Williams concluded by stating that there are a number challenges facing
organisations such as the FDA. Nanotechnology is a new technology and
the risks associated with its use are unknown. Currently there are limited
scientific data available to address public health concerns and it is
essential that there is timely and accurate reporting of all scientific
findings in order to inform the regulatory process. |
The
Pharmaceutical Journal