Encapsulated calcium carbonate suspensions: A drug delivery vehicle sensitive to ultrasound disruption

A calcium carbonate suspension, encapsulated within particles of calcium alginate hydrogel, is proposed as a drug delivery device susceptible to ultrasound disruption. Spheres approximately 1mm in diameter were prepared by the coaxial airflow method from mixtures of 1% sodium alginate (m/v) and each of 50%, 75% and 100% calcium carbonate (m/v) in distilled water. This product was subjected to cycles of 85 Watt ultrasound in 1 second on/off bursts via a lab sonication system until fully disintegrated, a process requiring between 8 and 20 minutes depending upon initial calcium carbonate concentrations. The spheres subjected to vortex did not demonstrate any signs of mechanical degeneration after 30 minutes. Before use as a model implant, further work is required to develop a method of drying the particles to make them impermeable to drug diffusion before the time of their disruption with ultrasound.