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Flurbiprofen release from eudragit RS and RL aqueous nanosuspensions: a kinetic study by DSC and dialysis experiments

Abstract

The present work investigated the release of Flurbiprofen (FLU) from Eudragit RS100 (RS) and Eudragit RL100 (RL) nanosuspensions to a biol. model membrane consisting of Dimyristoylphosphatidylcholine (DMPC) multi-lamellar vesicles (MLV). This release was compared with those obsd. from solid drug particles as well as with dialysis expts. Nanosuspensions were prepd. by a modification of Quasi-Emulsion Solvent Diffusion technique. Drug release was monitored by the Differential Scanning Calorimetry (DSC). FLU dispersed in MLV affects the transition temp. (Tm) of DMPC liposomes, causing a shift towards lower values. The temp. shift is modulated by the drug fraction present in the aq. lipid bilayer suspension. DSC was also performed, after increasing incubation periods at 37°C, on suspensions of blank liposomes added to fixed amts. of unloaded and FLU-loaded nanosuspensions, as well as to powd. free drug. Tm shifts, caused by the drug released from the polymeric system or by free-drug dissoln. during incubation cycles, were compared with those caused by free drug increasing molar fractions dispersed directly in the membrane during their prepn. These results were compared with the drug release and were followed by a classical dialysis technique. Comparing the suitability of the 2 different techniques in order to follow the drug release as well as the differences between the 2 RL and RS polymer systems, it is possible to confirm the efficacy of DSC in studying the release from polymeric nanoparticulate systems compared with the "classical" release test by dialysis. The different rate of kinetic release could be due to void liposomes, which represent a better uptaking system than aq. soln. in dialysis expts

Autori

PUGLISI - Giovanni

PIGNATELLO - Rosario

Altri Autori

Castelli Francesco
Messina Chiara
Sampietro Maria Grazia