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 biological model membrane consisting of Dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles (MLV). This release was compared with those observed from solid drug particles as well as with dialysis experiments. Nanosuspensions were prepared by a modification of QuasiEmulsion Solvent Diffusion technique. Drug release was monitored by the Differential Scanning Calorimetry (DSC). FLU dispersed in MLV affects the transition temperature (T m ) of DMPC liposomes, causing a shift towards lower values. The temperature shift is modulated by the drug fraction present in the aqueous lipid bilayer suspension. DSC was also performed, after increasing incubation periods at 37°C, on suspensions of blank liposomes added to fixed amounts of unloaded and FLU-loaded nanosuspensions, as well as to powdered free drug. T m shifts, caused by the drug released from the polymeric system or by free-drug dissolution during incubation cycles, were compared with those caused by free drug increasing molar fractions dispersed directly in the membrane during their preparation. 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 aqueous solution in dialysis experiments.

Enhancement of gemcitabine affinity for biomembranes by conjugation with squalene: Differential scanning calorimetry and Langmuir–Blodgett studies using biomembrane models

“…In addition, to gaining more information about the interaction prodrug/phospholipid, the experiments have also been carried out using squalene (2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene) and squalene acid (1,1 ,2-tris-nor-squalenic acid) used to allow the conjugation with gemcitabine (Scheme 1). Differential scanning calorimetry (DSC) is a nonperturbative technique largely employed to detect the effects exerted by biomolecules on the lipid bilayers of a cell-like membrane in the processes of entrapment and release inside lipid vesicles [9,10]. Lipid membranes (multilamellar vesicles, MLV, are usually employed as synthetic simplified biomembranes models) undergo a sharp phase transition from an ordered gel-like structure (L β ) to a disordered fluid-like structure (L α ).…”

Drug Release and Targeting: the Versatility of Polymethacrylate Nanoparticles for Peroral Administration Revealed by Using an Optimized In Vitro-Toolbox

“…Especially particle size, surface charge and the ability to interact with the mucosal surface define their transit time and potential to be taken up by specific cell types (8,16,37). However, very often the interaction of API and polymer as a crucial factor for drug release is neglected, although it is evident that a fast release of the API will lower the beneficial effect the polymeric shell implies (38,39). Eudragit® RS 100 is a positively charged polymethacrylic acid containing quaternary ammonium group.…”

Development,in vitroandin vivocharacterization of Eudragit RL 100 nanoparticles for improved ocular bioavailability of acetazolamide

“…It is a cationic polymer, which is capable of mucoadhesiveness at ocular site for longer time. Various drugs have been studied to deliver at ocular site via Eudragit Õ RL 100 Nanoparticles (Fessi et al, 1989;Castelli et al, 2002Castelli et al, , 2003Pignatello et al, 2002aPignatello et al, ,b, 2006Dillen et al, 2006;Das et al, 2010;Aksungur et al, 2011;Yoo et al, 2011;Zhang et al, 2012;Hao et al, 2013). In the present study, ACZ-loaded Eudragit Õ RL 100 nanoparticle suspension (ACZ-E-NPs) are prepared and its IOP lowering potential is studied.…”