Search

In the present work, the relationship between structural characteristics and functional performance in polyglycerol polyricinoleate (PGPR) stabilised water-in-oil (W/O) emulsions was investigated. Novel W/O emulsions with a PGPR concentration of 4%, and oil volume fractions (φO) of 0.7 and 0.8 showed the smallest mean droplet size (~5 μm) and highest emulsification index (~97%). Both W/O emulsions showed shear-thinning and elastic-dominant properties with a weak frequency dependence. Both W/O emulsions possessed superior thixotropic recovery properties with recovery percentages of 131.26% (φO = 0.7) and 114.56% (φO = 0.8). The thermo-responsive properties could be closely related to the PGPR aggregation induced by hydrophobic interaction and interfacial rearrangement. The present work helped to design and develop functional W/O emulsions as alternatives to butter spreads, bio-lubricants, and other thermo-responsive delivery systems.

A bilayer swellable drug-eluting ureteric stent (BSDEUS) is engineered and implemented, as a sustained drug delivery platform technology that enhances localized drug delivery to the highly impermeable urothelium, for the treatment of urothelial diseases such as strictures and carcinomas. On deployment, the device swells to co-apt with the ureteric wall and ensure drug availability to these tissues. BSDEUS consists of a stent spray-coated with a polymeric drug containing polylactic acid-cocaprolactone (PLC) layer which is overlaid by a swellable polyethylene glycol diacrylate (PEGDA) based hydrogel. In-vitro quantification of released drug demonstrated a tunable time-profile, indicating sustained delivery over 1-month. The PEGDA hydrogel overlayer enhanced drug release and transport into explanted porcine ureteric tissues ex-vivo, under a simulated dynamic fluid flow. A preliminary pilot invivo feasibility study, in a porcine model, demonstrated that the swollen hydrogel co-apts with the urothelium and thus enables localized drug delivery to the target tissue section. Kidney functions remained unaffected and device did not result in either hydronephrosis or systemic toxicity. This successful engineering of a bilayer coated stent prototype, demonstrates its feasibility, thus offering a unique solution for drug-based urological therapy. ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore) NMRC (Natl Medical Research Council, S’pore) Accepted version