ABSTRACT
Objective To compare two effective preparation methods for paclitaxel-loaded lipid microbubbles, and to evaluate the physiochemical properties as for acoustic activated drug delivery. Methods Paclitaxel-loaded lipid microbubbles were prepared with two methods: one was mixed with phospholipids directly (Ⅰ); the other was added in triacetin, then mixed with phospholipids (Ⅱ). Concent ration, size, pH, drug entrapment efficiency, drug-loading amounts of these two kinds of paclitaxel-loaded lipid microbubbles were studied, while drug release with ultrasound and tumor imaging enhanced on rabbit breast tumor were observed. Results There was no significant difference in tumor imaging between two kinds of microbubbles which could be ruptured by low energy ultrasound. Compared with Ⅰ, the mean diameter of Ⅱ decreased significantly ([ 1.07±0.38] μm vs [2.79± 0.41] μm, P<0.01), the surface potencial was higher ([19.10±0.32] mV vs [-5.90±0.21] mV, P<0.01), whereas entrapment efficiency and drug-loading amounts increased markedly ([ 95.00±1.22]% vs [36.10±4.74]%, P<0.01; [5.60±0.11]% vs [0.50±0.04]%, P<0.01). Conclusion The Ⅱ paclitaxel-loaded lipid microbubbles added triacetin have an important clinical value.
ABSTRACT
Objective To study the dynamic changes of transendothelial electrical resistance (TEER) on our in vitro model of brain blood barrier (BBB) made from primary culture of BALB/c mouse brain microvascular endothelial cells (BMVEC), and to explore the relation between TEER and BBB permeability, and search for the best culture condition. Methods BMVEC were isolated from BALB/c mouse and cultured on a transwell insert with special micro-pore. The cells were identified with immunohistochemical methods and electron microscope. TEER over BMVEC was measured after BBB model establishment for determining the 3H-Glucose permeability of BBB in vitro. Results BMVEC cultured in the transwell insert exhibited typical "flagstone" appearance and in a tight monolayer structure under electron microscope. Immunohistochemical detection of ZO-1 protein, a marker antigen of tight junction, showed smooth, continuous and tight junctions between confluent BMVEC. TEER over BMVEC monolayer increased to (346?10) ?/cm2 when the permeability for 3H-Glucose was decreased to the minimum. Conclusion BBB model in vitro made from primary culture of BMVEC in transwell has the basic characteristics of BBB in morphology, electrical resistance and permeability.