A novel fluoride anion modified gelatin nanogel system for ultrasound-triggered drug release

Purpose. We prepared a novel fluoride anion-modified gelatin nanogel system and investigate its pattern of ultrasound-triggered drug release. Methods. Adriamycin (ADM) gelatin nanogel modified with fluoride anion (ADM-GNMF) was prepared by a modified co-precipitation method with fluoride anion and sodium sulfate. The loading and encapsulation efficiency of ADM were measured by HPLC. The size and shape of ADM-GNMF were determined by electron microscopy and photo-correlation spectroscopy. The diameter distribution changes and drug release efficiencies of ADM-GNMF, before and after sonication, were measured by a submicron particle size analyzer, an ultrasound generator, an ultrasound generator and an automatic sampler. Results. The ADM-GNMF was stable in solution with an average diameter of 46±12 nm; the encapsulation and loading efficiency of adriamycin were 87.2% and 6.38%, respectively. The ultrasound-triggered drug release and size change were most efficient at a frequency of 20 kHz, power density of 0.4w/cm², and a 1~2 min duration. Under this ultrasound-triggered condition, 51.5% of drug in ADM-GNMF was released within 1~2 min, while the size of ADM-GNMF changed from 46 ± 12 nm to 1212 ± 35 nm within 1~2 min of sonication and restored to its previous size in 2~3 min after the ultrasound stopped. In contrast, 8.2% of drug in ADM-GNMF was released within 2~3 min without sonication, and only negligible size changes were found. Conclusions. The ADM-GNMF system efficiently released the encompassed drug in response to ultrasound, offering a novel and promising controlled drug release system for targeted therapy for cancer or other diseases.