The freeze-drying process lasted 48 h and was carried out in a freeze drier Alpha 1-4 LD/2-4 LD-2 (Martin Christ, Gefriertrocknungsaniagen GmbH, Osterode, Germany). It was operated at −84 °C at a chamber pressure of 0.04 mbar.
Thefreeze-drying process lasted 48 h and was carriedout in a freeze drier Alpha 1-4 LD/2-4 LD-2 (MartinChrist, Gefriertrocknungsaniagen GmbH, Osterode,Germany). It was operated at −84 °C at a chamber pressureof 0.04 mbar.