Chemistry Reference
In-Depth Information
treatment is a matter of formulation and of delivery, taking into account all factors
that may interact with the bioactive molecule.
Drug delivery systems refer to a formulation or a device that ensures the admin-
istration of a bio-active compound (medicine), and ensures as well an enhancement
of the therapeutic effect with respect to the safety of administration. A competitive
drug delivery system covers all essential aspects of pharmacokinetics and pharma-
codinamy: rate, time and place of release of the bio-active compound according to
host factors (pH, etc.) and formulation factors (Asadujjaman and Mishuk
2013
).
It is very well known that interactions between cells and external substrates hap-
pen at microscale levels. To serve this scope, an ideal drug delivery system has to
facilitate this type of interactions. Thereby, inter- and trans-disciplinary research
focused on development of micro- and nano-devices with applicability in drug and
gene delivery systems, as well as in biosensors and tissue engineering. Most used
materials for these purposes are polymers because of their adjustment ability to cells
and molecules (Caldorera-Moore and Peppas
2009
). Already classic examples are
silicon or polymeric micro-membranes designed to obtain implantable biocapsules
which produce the immunoisolation of pancreatic islet cells with intention to control
pancreatic hormonal secretion intervening in diabetes management (Tao and Desai
2003
). Establishing a good glycemic equilibrium means to assure a good state of
health, and a good quality of life. Biosensors are already used to assess different
biological parameters (traditional ones are tetraethoxysilane derived sol-gel com-
posite). A new glucose biosensor based on covalent immobilization of enzyme in
sol-gel composite showed an improved electrochemical and biosensing stability (Fu
et al.
2011
).
Self-aggregates of amphiphilic prodrugs define the so-called self-assembled drug
delivery systems. Antiviral nucleoside analogues were processed in order to obtain
amphiphilic prodrugs, then liposome-like self-aggregates in water were obtained.
These systems have affinity for immunocompetent cells (e.g., macrophages), thus
being highly effective in viral infections, inclusively HIV infections (Jin et al.
2008
).
Ajami and Aguey-Zinsou (
2012
) imagined a new system for active bio-molecules
delivery, by modifying the surface of titanium with self-assembled mono-layers. The
technological process implied the electropolishing of the titanium surface in order to
obtain the above mentioned mono-layers containing OctadecylTrichloroSilane at low
temperature (10
â—¦
C). This surface showed an increased capacity to immobilize and
release antibiotics over a consistent period of time (up to 26 days). This technology
shows high potentiality to release active therapeutic agents from implant surfaces.
Amoxicillin (hydrophilic antibiotic) was studied by means of drug delivery and ef-
ficiency using a new carrier, namely SBA-15 particles (Sevimli and Yilmaz
2012
):
loading efficiency with amoxicillin was monitored using the UV spectrophotome-
try. Release profiles are sustained and not so prolonged, but amoxicillin release can
be controlled.
Naproxen (important and significant non-steroidal anti-inflammatory drug) was
loaded both in the amine-modified and unmodified mesoporous silica SBA-15
(Halamová et al.
2010
). The release of naproxen was made in a faster manner from
the unmodified carrier, but, in time, the amount of released naproxen was larger from
