FLORINA ARDELEAN, RAZVAN SUSAN, FLORIN BORCAN, ALINA MOACA, DIANA SIMONA ANTAL, CODRUTA SOICA, ROXANA MOLDOVAN, DELIA BERCEANU VADUVA, DANIELA MARTI SYNTHESIS AND PHYSICO-CHEMICAL EVALUATION OF POLYURETHANE MICROSTRUCTURES FOR TRANSMEMBRANE DELIVERY OF REYNOUTRIA JAPONICA EXTRACT Polymer microstructures containing plant extracts are a novel technique used to increase the bioavailability of active agents with low aqueous solubility. Japanese knotweed (Reynoutria japonica) is an invasive plant with multiple biomedical properties. The aim of the present study was to obtain and characterize polyurethane microstructures used as a drug delivery system of a Japanese knotweed extract. The results indicate the obtaining of microstructures with an almost neutral pH, with sizes between 540 and 1134 nm, with a medium stability against the tendency to form clusters and a very good thermal stability. These first results present the potential of the obtained polyurethane microstructures as candidates for the transmembrane drug delivery of Japanese knotweed extracts, as a starting point for further bioactivity investigations.