Effect of Sonication, Liquid Nitrogen Cooling During Crystal Growth and Heating Process on Crystal Growth of Paclitaxel Coated on a FullyBioabsorbable Poly (L-Lactic acid) Stent

Abstract

To achieve appropriate efficacy of paclitaxel (PTX) used in drug eluting stents, uniform PTX coating on the stent and increased initial release of PTX leading to immediate therapeutic level of the drug are required. The present study investigated whether either restriction of crystal growth though sonication and subsequent liquid nitrogen cooling, or formation of anhydrous PTX crystals through heating microcrystals after seeding and crystal growth could increase PTX initial release coated on a fully-bioabsorbable poly(L-lactic acid) stent. The sonication and subsequent liquid nitrogen cooling of the growing PTX crystals could prevent stable attachment of the crystals onto the stent surface. In addition, the initial PTX release from the stent applied sonication during the crystal growth process followed by heating showed five times as high as the stent without heating, which indicated the heating improved the PTX release from the stent at early phase. These results suggested that PTX was changed into an anhydrous soluble form.