An administration device comprising an array of needles, one or more fluid agents, and at least one hydrogel is described. The device can simultaneously deliver a plurality of fluid agents along respective axes into a tissue. The use of hydrogel leads to constrained delivery of the fluid agents. The constrained delivery of an agent is also achieved by depositing a drug implant into a tissue. The effect of an agent on the tissue can be evaluated thereafter. In addition, the invention is directed to treating muscle diseases by delivering a therapeutic agent in vivo, and the use of reporter tissues for candidate drug evaluation, detecting and characterizing resistance.
