Violeta PAŞCALĂU

CONTROLLED DRUG DELIVERY SYSTEMS. HYDROGELS
This article intends to present a review about responsive polymer
systems used in controlled drug delivery applications. It was definite the
concept of drug delivery as an ability to sustainable and constantly deliver the
therapeutic agent, in order to solve the problem of conventional drug therapy
where drug is released immediately after medication. This review gives
information on polimeric materials concerning the relationship between their
design and the mechanism of drug release. Hydro gels are three-dimensional,
hydrophilic, polymeric network, capable of imbibing large amounts of water or
biological fluids, and are used in biomedical applications. Hydro gels are
stimuli-responsive materials, that can undergo abrupt volume change in
response to small changes in environmental parameters: temperature, pH, ionic
strength. This article discusses the classification of drug delivery systems
according to the mechanism controlling the drug release, and a few words
about novel polymers responsive to external applied magnetic and electric
fields.
Keywords: stimulus-responsive polymers, hydrogels, controlled
release drug
Cuvinte cheie: polimeri receptivi la stimuli, hidrogeluri, eliberarea
controlată a medicamentelor

26 SISTEME DE ELIBERARE CONTROLATA A

POLYSACCHARIDES USED IN OBTAINING HYDROGELS
FOR CONTROLLED DRUG DELIVERY SYSTEMS
This paper is a review of the most important papers related to
polisaccharides studied and used in hydrogels systems for controlled drug
delivery. Among the numerous macromolecules that can be used to obtain
hydrogels, polysaccharides present many advantages comparatively to
synthetic polymers being largely found in living organisms. Coming from
renewable sources, polysaccharides also have frequently economical
advantages over synthetic polymers, because they are non-toxic, biocompatible
and bioavailable, showing such physico-chemical proprieties that make them
suitable for applications in drug delivery systems. Focusing on the ability of
polysaccharides to form hydrogels in a great diversity of compositions it is well
understood that safer and more realistic approaches in the therapy of diseases
will be achieved in the days to come.
Key words: polysaccharides, hydrogels, controlled release drug
Cuvinte cheie: polizaharide, hidrogel, eliberarea controlată a medicamentelor

27 POLIZAHARIDE FOLOSITE ÎN OBŢINEREA