Lessons Learned from Pharmaceutical Nanomaterials - Safety of Nanomaterials along Their Lifecycle - page 110

6.1 WHAT ARE PHARMACEUTICAL NANOMATERIALS?
“NANOPARTICLES” FROM A PHARMACEUTICAL POINT OF VIEW
These days there are many controversial discussions about nanoparticles. The term
nanoparticles stands for numerous objects in the nanoscale range including particle
manufactured for medical use, particle generated at the industrial scale for surface
coatings, electronics, energy, or consumer products, and last but not least pollution
particles. Searching for “nanoparticles” via Scopus, the big citation and abstract
database, presents approximately 180,000 publications of the last few decades. Only
45,000 of these publications are in medical, pharmaceutical, or biological journals.
The unspecific vocabulary is not helpful in this discussion as it implies that size
would be the main crucial property. The particle size is decisive for the interac-
tion potential with biological surroundings, by determining the accessibility and the
interaction surface. Other physicochemical properties of nanoparticles, however,
contribute in terms of their hazard potential. Hence, being more precise in defini-
tion makes it easier to reach a realistic appreciation of both, the promises and fears
connected to nanotechnology. Studies on the impact of combustion particles on
environment or human health are important for risk assessment. Some of them are
worst case scenarios of intoxication with nanoparticles not intended for human use.
These results should not be extrapolated to particles for deliberate use in humans
as is for nanomedicine. Applying nanotechnology for medical purposes means raw
materials, manufacturing processes, and quality control are chosen and designed to
achieve safest possible products. Nanomedicine, which is defined by the European
Technology Platform on NanoMedicine as the application of nanotechnology in
health care, exploits the improved and often novel physical, chemical, and biological
properties of materials at the nanometric scale (NanoMedicine 2005). As nanomedi-
cine also includes devices for medical use we term the nanoformulated drug delivery
systems as “nanopharmaceuticals,” which offer many advantages such as enhanced
solubility, higher bioavailability, reduction of side effects, targeting specific tissues,
or protection of unstable drugs. When this chapter is reporting about nanopharma-
ceuticals, it aims to deliver some examples of how the potential of nanotechnology
can be harnessed for pharmaceutical applications. A brief description and appraisal
of the current usability of nanopharmaceuticals is presented in section 6.1. Few con-
siderations regarding the chances and risks depending on the application route are
given in section 6.2. Translation into safe medicine needs careful evaluation of par-
ticle characteristics (section 6.3.1) and their biological effects (section 6.3.2), which
can bring us closer to the goal of safety prediction based on physicochemical par-
ticle properties as it would be needed for quality/safety by design approaches (sec-
tion 6.4). Finally, section 6.5 reviews selected nanopharmaceuticals on the market to
learn from some best case examples.
6.1.1 d esigns of n anoPharmaCeutiCals
Nanopharmaceuticals can roughly be divided into two groups: The first group
includes nanocrystals , which are nanosized, stabilized drug particles (consisting
the active ingredient itself as the main material). The second group is drug-carrier