Title screen

[References: 63 tit.]

The combination of an efficient encapsulation method of small water-soluble substances with a stimuli-responsive release of defined quantity remains a challenging task. A novel drug delivery system (DDS) representing a free-standing PLLA microchamber arrays film and its application as the cover for implantable endovascular stent are reported in this work. The proposed DDS preparation method is consisting of a patterned polydimethylsiloxane (PDMS)-stamp dip-coated into a polymer solution followed by drug loading and sealing it by polymer pre-coated substrate. It was shown that using 1?wt% PLLA solution is optimal for obtaining microchamber arrays with an individual cargo capacity of 2.88?Ч?10-9 µg, which was successfully loaded by model drug substance Rhodamine B. Rhodamine B was completely released in vitro during 13?days in PBS at 37?°C by diffusion. It was demonstrated that low-frequency ultrasound (LFUS, 20?kHz) allows triggering RhB release due to microchamber damage and detachment of individual PLLA microchambers over time. LFUS exposure time up to 25?s led to RhB release of up to 8.4?Ч?10-4 µg (approximately 55%) from microchambers located on the flat substrate; up to 5.2?Ч?10-4 µg from microchambers located on the stent with using a simplified vessel model. Furthermore, the free-standing printed PLLA microchamber arrays were demonstrated to be applied as endovascular stent cover that can be used for complementary pharmacological effect, for example, triggered local delivery of anticoagulants.