Use freezing/thawing treatment prepared a high toughness composite hydrogel from hydrophobic drug-loaded silicone oil dispersed in poly(vinyl alcohol) solution. The hydrogel owned a relatively stable structure through fluorescent microscopy

silicone oil was dispersed and permeated in the hydrogel matrix as microdroplets

no aggregation or migration were observed when the hydrogel sample was placed stationary after 5 weeks. The mechanical properties of hydrogel enhanced proportionally with increasing the silicone oil content

indicating silicone oil not only act as drug reservoirs dispersed within the hydrogel matrix

but also improved the mechanical properties for strong adsorption effect of PVA chains on hydrophobic surfaces.Ultrasound is used to control trigger the hydrophobic drug release from the hydrogel

the result showed the drug were instantly and rapidly released under ultrasound exposure. Mechanism of ultrasound controlled drug release is studied in this paper

and the results indicate the mechanical effect is the main reason.