Preparation and evaluation of differently sulfonated styrene-divinylbenzene cross-linked copolymer cationic exchange resins as novel carriers for drug delivery

Control of Ion Transport in Sulfonated Mesoporous Polymer Membranes

We investigated proton conductivity and the permeability of monovalent cations across sulfonated mesoporous membranes (SMMs) prepared with well-defined pore sizes and adjustable sulfonic acid content. Mesoporous membranes with three-dimensionally continuous pore structure were produced by the polymerization-induced microphase separation (PIMS) process involving the reversible addition-fragmentation chain transfer (RAFT) copolymerization of styrene and divinylbenzene in the presence of a polylactide (PLA) macrochain transfer agent and subsequent PLA etching. This allowed us to control pore size by varying PLA molar mass. Postsulfonation of the mesoporous membranes yielded SMMs whose pore structure was retained. The sulfonic acid content was adjusted by reaction time. While proton conductivity increased with increasing ion exchange capacity (IEC) without noticeable dependence on the pore size, ion permeability was strongly influenced by the pore size and IEC values. Decreasing pore size and increasing IEC resulted in a decrease in ion permeability, suggesting that ions traverse across the membrane via the vehicular mechanism, through the mesoporous spaces filled with water. We further observed that the permeability of the vanadium oxide ion was dramatically suppressed by reducing the pore size below 4 nm, which was consistent with preliminary vanadium redox flow battery data. Our approach suggests a route to developing permselective membranes by decoupling proton conductivity and ion permeability, which could be useful for designing separator materials for next-generation battery systems.

Development and evaluation of orally disintegrating tablets containing the mosapride resin complex

The purpose of this study was to prepare a mosapride citrate-resin (Amberlite® IRP 88) complex and orally fast-disintegrating tablets of the resin complex. The resinate complex of mosapride-Amberlite® IRP 88, mass ratio 2:1, was prepared in an ethanol-water solution. The effects of alcohol concentration, temperature, and pH of the solution on complex formation were evaluated. The complex physicochemical properties were characterized by differential scanning calorimetry, X-ray diffraction and scanning electron microscopy. Orally disintegrating tablets were prepared by direct compression and were optimized using the response surface method. Optimized orally fast-disintegrating tablets disintegrated within 18 s. The pH dependence of mosapride release from the tablet decreased drug dissolution in simulated saliva, whereas it promptly released in the pH 1.0 solution. The data reported herein clearly demonstrate that tablets containing the mosapride-Amberlite® IRP 88 complex for oral disintegration could be particularly useful for patients with swallowing difficulties.