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Papers by Frederic Eeckman

International Journal of Pharmaceutics, 2004

In the course of the development of a new drug delivery concept, four thermosensitive copolymers ... more In the course of the development of a new drug delivery concept, four thermosensitive copolymers of poly(N-isopropylacrylamide) (PNIPAAm), with phase transition temperature slightly higher than 37 • C, were synthesised and used as time-controlled drug delivery agents.

International Journal of Pharmaceutics, Jul 17, 2001

Poly-N-isopropylacrylamide (PNIPAAm) thermosensibility makes this polymer a very attractive candi... more Poly-N-isopropylacrylamide (PNIPAAm) thermosensibility makes this polymer a very attractive candidate for controlled drug delivery systems. The polymer possesses a lower critical solution temperature (LCST) which was found to be around 32°C in pure water, but which can be affected by the medium composition, i.e. presence of salts or surfactants. The knowledge of the effects of such substances on the LCST is very important while using PNIPAAm as a controlled drug delivery agent. The influence of a number of physiological and non-physiological salts and surfactants has been studied. The results obtained show that the addition of salts provokes an important decrease of the LCST of the polymer (salting out effect). A strong influence of the valence and of the size of the anions of the halide group was found. As to the surfactants, according to their type and concentration, a decrease or an increase of the LCST or even no effect at all were found. The effect of the GI secretions on the PNIPAAm phase separation temperature is also discussed.

International Journal of Pharmaceutics, Jul 8, 2002

The purpose of this work is to develop a new delivery concept making a thermosensitive polymer ba... more The purpose of this work is to develop a new delivery concept making a thermosensitive polymer based on poly(N-isopropylacrylamide) (PNIPAAm) useful as a time-controlled drug release device, without any temperature changes of the dissolution medium. It was previously found that some salts induce a decrease of the polymer lower critical solution temperature (LCST). Use is here made of that property to show that salt concentration variations can be used as a substitute for temperature changes to make the polymer coating of compression-coated tablets soluble or insoluble, consequently creating a possible new concept of drug delivery control from delivery systems containing thermoresponsive polymers. The obtained results show the influence of the type and amount of salts incorporated into compression-coated tablets on the release lag time of a model drug.

International Journal of Pharmaceutics, 2001