Tray apparatus for freeze-drying biologicals having a predetermined unit dosage

Claim 1

Tray apparatus for lyophilizing a solution of biological material into pledgets of predetermined unit dosages of the biological material for use in a freeze drying apparatus having a chamber within which is positioned a plurality of spaced apart superposed thermally controlled shelves, comprising: an upper plate having a length, a width and a thickness and having a plurality of wells extending downwardly from a portion of an upper surface thereof into said upper plate, each of said wells being conical, having downwardly sloping, converging side walls, and terminating in a concave dome shape and having a volume substantially equal to the volume of a solution of the biological material in a liquid, said solution being of such concentration and volume as to yield, upon lyophilization, the predetermined unit dosage size of pledget, each well terminating at a location spaced from a lower continuous surface of said upper plate; a lower plate having a length, a width and a thickness, an upper continuous surface of said lower plate laminated to said lower continuous surface of said upper plate in a thermally conductive manner, said lower plate comprising a material having a greater thermal conductivity than the material comprising said upper plate; a sheet of thermal insulating material having a length, a width and a thickness, said thermal insulating material having a continuous lower surface with a surface area substantially equal to or greater than the surface area of said upper surface of said upper plate, said lower surface of said thermal insulating material positioned above said upper surface of said upper plate to establish a thermal gradient through said upper plate wherein lower points in the wells are at lower temperature than upper points in the wells to insure that said solution freezes from the bottom to the top, said thermal insulating material having a lower thermal conductivity than either said upper or lower plates; and, a separator comprising a continuous rigid sheet positioned between said thermal insulating material and said upper plate, said separator having a lower surface with a surface area substantially equal to or greater than the surface area of said portion of said upper surface of said upper plate from which said plurality of wells extend.