Study on the release behaviors of berberine hydrochloride based on sandwich nanostructure and shape memory effect.

Nanofibrous drug delivery systems (DDSs) recently have attracted remarkable interest, especially their potential to program dosage of the encased drug intelligently. Despite this, the exploration of efficient strategy to precisely program drug release from nanofibrous DDS still remains a significant challenge. In this study, we electrospun a near-body temperature (Ttrans ≈ 42 °C) sensitive shape memory polyurethane in three stages through sequential electrospinning technology, and prepared a sort of sandwich structural membrane, comprising of top, inner and bottom layers, wherein a natural antibacterial agent, berberine hydrochloride (BCH), was imbedded inside the middle layer. As demonstrated by the results obtained from tensile testing and morphology characterization, the prepared sandwich structural membrane and the nanofibrous membrane with homogenous structure exhibited not only desirable mechanical properties but also surface morphologies. In addition, the release period can be significantly prolonged in virtue of the sandwich structure. As revealed by the experiment of in vitro drug release, it took nearly 144 h to release 80 wt% BCH from sandwich structural membrane, while as little as 72 h was observed to release the same amount of BCH from that with homogenous structure. More interestingly, the encapsulated BCH is capable to be released in a controlled manner owning to the thermo-sensitive shape memory effect, and the release rate of BCH can be accelerated by stretching and fixing the nanofibrous membranes into certain ratios prior to release. Collectively, this study provides a facile strategy to design and prepare a reliable and smart DDS, i.e. sandwich structural membrane, which may enhance the availability of BCH and also intelligently avoid the bacterial infection.