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A tremendous amount of work has been concentrated
worldwide in the past two decades on the pharmaceutical and medical research
and development of drugs with improved temporal and spatial site-specificity
which can be embedded in medical devices like teeth fillings and drug eluting
coronary stents, that is, targeted drug delivery systems. Controlled drug
delivery occurs when a biodegradable biocompatible substance (i.e. biopolymers)
is judiciously combined with a drug or other active agent in such a way that
the last one is released from the material in a predesigned manner. The release
of the active agent may be constant over a long period, it may be cyclic over a
long period, or it may be triggered by the environment or other external
events. Oral solid dosage formulations are a convenient method
of drug delivery and account for a large proportion of pharmaceutical products.
Drug substances are not routinely administered in the pure state and functional
components is a heterogeneous mixture of many components, with individual
particles of the order of micrometers in size. Additionally, solid dosage
design can include strategies to precisely control the rate of drug delivery (for
example, sustained release), typically using one or more polymer coatings which
must reach a specific body site and possess an appropriate release profile. The new challenges and directions in drug delivery
coatings research include synthesing new materials and developing already
existing materials for farmaceutical applications. Also, the reduced toxicity,
highly targeted delivery and improved (prolonged or sustained) release profile
are highly desirable. Nowadays, structures that combine drug agents and
biopolymer coatings with controlled thickness promise to fulfill all
aforementioned requirements. The best results has been obtained by Matrix
Assisted Pulsed Laser Evaporation (MAPLE). This technique has been accomplished
and developed in Romania in our laboratory since 2003, beign included in a PhD
thesis elaborated in the group who started this project. MAPLE was developed at
the United States Naval Research Laboratory in the late 90’s. MAPLE is
basically distinguished from the conventional pulsed laser deposition technique
by the target preparation and significantly different laser material
interaction and transfer mechanism. It provides, however, a more gentle
mechanism for transferring many different compounds that include small and
large molecular weight species such as sugars and polymeric molecules, from the
condensed phase into the vapor phase. Extension of MAPLE to biopolymers is
interesting owing to its reliability and good control of deposition process
parameters (thickness, interface control, porosity). The MAPLE processing
relies on achieving a modulatory release profile of drug particles by varying
the thickness and composition of biodegradable polymer in a multilayer
implementation. Potential end-users of nanostructured biopolimer coatings with controlled porosity are drug companies. Companies are intensifying efforts to improve their technologies and many are doing so by collaborating in strategic partnerships, joint ventures, and mergers and acquisitions. At a preliminary market study several potential Romanian and European drugs companies have already showed their interest in the MAPLE nanotechnology introduced by us. |