Spray drying is generally performed under an inert atmosphere such as nitrogen or argon, with an inlet temperature ranging from 125??? C. to 200??? C. and an outlet temperature ranging from 75??? C. to 150??? C. Rotary evaporation is generally performed at a bath temperature of from 25??? C. to 90??? C. and at a pressure of from 10 mmHg to 760 mmHg, preferably at a bath temperature of from 40??? C