Microprojection applicators and methods of use

An applicator, comprising:

• a rigid planar plate member with an upper surface on a first side of the plate member and a lower surface on a second side of the plate member, the plate member having at least one opening therethrough;
• a blocking element in contact with the upper surface of the plate member and being capable of moving between a first position and a second position;
• a plunger having a proximal end, a distal end on which at least one microprojection is retained, and a shaft extending therebetween, at least a portion of the proximal end rests directly on and is at least partially retained by the blocking element in its first position;
• wherein, the plunger is slidably accommodated within the opening of the plate member;
• an energy-storing element positioned between the lower surface of the plate member and the distal end of the plunger;
• and
• an actuating member having an external surface for application of a force, and having at least one surface in mechanical communication with the blocking element, wherein the actuating member moves the blocking element from its first position to its second position when a force is applied to the external surface of the actuating member, thereby to effect release of the plunger and the energy-storing element.