Methods for preparing dried pellets of biological materials are described. The pellets can have a substantially spherical shape and are prepared by freezing droplets of a liquid composition of a desired biological material on a solid surface followed by microwave vacuum drying the frozen droplets. These methods are useful for preparing dried pellets having a high concentration of a desired biological material, in particular a therapeutic protein or vaccine, and which have a faster reconstitution time than lyophilized powder cakes prepared in vials.
