Poli(N-vinylcaprolactam - maleic acid) have been synthesized by radical copolymerisation, and characterized by FTIR, 1H NMR, potentiometric titration. The obtained copolymers presented lower critical solution temperature (LCST) that is influenced by the maleic acid content from the copolymer, by the solution pH, and also by the concetration.

Micropartcles were obtained by the crosslinking of N-vinylcaprolactam - maleic acid copolymers with hexamethylenediamine using suspension of DMSO in parafin oil.

The water retention of the obtained microparticles is influenced by the pH and temperature. The microparticles were loaded with model drugs: diphenhydramine, metoclopramid. The release profiles in pH buffers show a burst release, independent of the pH, explained by the presence of the salts that screen the electrostatic attraction between the drug and the polymer matrix. In order to solve this problem, the ionic microparticles were encapsulated into water-insoluble polymeric matrix: cellulose acetate butyrate microcapsules.

SEM image of cellulose acetate butyrate microcapsules containing drug loaded microparticles based on N-vinylcaprolactam-co-maleic acid copolymers	Release profiles of metaclopramid from unencapsulated microparticles based on N-vinylcaprolactam-co-maleic acid copolymers and from encapsulated microparticles in phosphate buffer pH=7.4

The hydrogen bonds interaction between poly(maleic acid-alt-styrene) (MAc-St) and poly(N-vinylcaprolactam) (PVCL) was studied by turbidimetry, dynamic light scattering, viscometry, fluorescence and FTIR spectroscopy.

Optical density as function of the MAc-St content in the mixture with PVCL at pH=2.7 and 2.5	Variation of the reduced viscosity ratio with the composition of the mixture

Beads were obtained using the complexation of MAc-St and PVCL in acidic pH. The drug release from the obtained beads is controlled by the pH.

SEM image of the beads based on MAc-St and PVCL	Influence of the pH on the drug release from the MAc-St/PVCL beads