Rheological characterization of polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer (Soluplus®) water dispersions

Abstract

Soluplus® is a graft copolymer, with PEG and vinylcaprolactam/vinyl acetate side chains, recently available as excipient used to promote fast drug release in pharmaceutical dosage forms and as solubility enhancer. Despite this copolymer is reported to be able to act as a thickening additive and even as gelling agent as a function of temperature, there is a lack of information about the physical–chemical properties of its water dispersions. Thus, the aim of this paper is to investigate the influence of Soluplus® concentration and experimental temperature on the modification of the rheological properties of Soluplus® water dispersions. The results clearly indicated the influence of both the studied parameters and of their interactions on the Soluplus® thickening ability. Although some systems appear gel by human perception at 37 °C, the mechanical spectra demonstrated the lack of the formation of a tridimensional network structure. Overall, in all the analyzed temperatures and concentrations, the systems always behave as a “rheological” dilute or semidilute polymer solution

Release Problems for Nifedipine in the Presence of Soluplus

“…It was chosen for comparison in the release of nifedipine from co-precipitate for its ability to form a gel at about 37°C, similarly to soluplus [38] . Due to this property this sucrester does not drive the notable improvement of nifedipine release, differently to what reported [39][40][41] . No micro-precipitate was observed, since the different molecular structures for soluplus and sucrester prevent interactions with nifedipine, responsible of decreasing hydrophilicity of the system and of the precipitate formation: the gelling properties of the carrier alone account for the reduction of the release extent, but not for the formation of micro-particulate.…”

Soluplus solutions as thermothickening materials for topical drug delivery

“…To the best of our knowledge, only a single peer‐reviewed article describes the thermothickening of soluplus . Cespi et al . investigated the effect of temperature on the rheology of soluplus solutions between 5 and 35% (w/w).…”

The use of Rheology Combined with Differential Scanning Calorimetry to Elucidate the Granulation Mechanism of an Immiscible Formulation During Continuous Twin-Screw Melt Granulation

“…Soluplus ® (X10 = 184 μm, X50 = 301 μm, X90 = 478 μm) is a graft copolymer consisting of three parts, being polyvinyl caprolactam (57%), polyvinyl acetate (PVA) (30%) and PEG 6000 (13%) (22). The polymer had an initial moisture content of 2-3% and was wellprotected during storage.…”