Methods and devices are provided for delivering a drug to or withdrawing a
fluid from a biological tissue, such the skin, sclera, cornea, and
conjunctiva. One method includes the steps of inserting at least one
microneedle into the biological tissue; partially retracting the at least
one microneedle from the tissue; and then delivering at least one drug
formulation into the biological tissue via the partially retracted at
least one microneedle. The microneedle deforms and penetrates the
biological tissue during the insertion step, and the retraction step at
least partially relaxes the tissue deformation while maintaining at least
part of the tissue penetration, facilitating drug delivery or fluid
withdrawal.