Study on formability of solid nanosuspensions during solidification: II novel roles of freezing stress and...

The freezing stress and cryoprotectants were known to be the crucial factors for solidification formability of nanosuspensions during freeze-drying. However, there has been controversy as to whether an aggressive or conservative freezing stress (freezing temperature or freezing rate) prevents from irreversible aggregation of nanosuspensions. And the screening of cryoprotectants for solidification formability of nanosuspensions has largely relied on empirical approaches. A systematic investigation was presented herein regarding the effect of both the freezing stress and property of cryoprotectants on solidification formability of drug nanosuspensions during freeze-drying. It was found that at different freezing stresses (-20 °C, -80 °C, and -196 °C), the redispersibility of BCN, NGN, RCN, and RVL nanosuspensions stabilized, respectively, by seven stabilizers, was RDI(-20 °C)>RDI(-80 °C)>RDI(-196 °C). But the redispersibility of UDCA and OCA nanosuspensions stabilized, respectively, by seven stabilizers, was RDI(-20 °C)