Patent ID: 7635344

Claim:
A method of preparing a composition, comprising: providing a packaging material containing a mixing device, the mixing device comprising: a housing having a chamber therein, the chamber having a first length and containing a first material; a piston slideable within the chamber, the piston having a second length that is greater than the first length; a container having a second material therein, the container having a septum; a fluid passageway disposed longitudinally through the piston; a piercing structure associated with the piston, the piercing structure having a base portion, a head portion and a tube portion extending between the base portion and the head portion; and a valve associated with the piston and orthogonally traversing the fluid passageway controlling fluid passage through the passageway; without exposing the device to an environment external to the packaging material, puncturing the septum of the container with the piercing structure, the piercing structure being configured such that the tube portion traverses the septum and the head portion is retained within the container after the puncturing; without exposing the device to an environment external to the packaging material, repositioning the valve from a closed position to an open position; with the valve in the open position, sliding the piston in a first direction from a first position within the chamber to a second position within the chamber, the sliding drawing one of the first and second components through the piston; mixing the first and second materials to form a mixture, the mixing comprising after sliding the piston in the first direction and with the valve in the open position, sliding the piston in a second direction opposite the first direction, and subsequently sliding the piston again in the first direction; and drawing the mixture into the chamber through the piston.