the apparatus comprises a mold assembly including at least one bore therethrough having a cavity therein defining the shape of the finished microneedle shape to be formed therein . the bore has an inlet opening and an exit opening . the apparatus also comprises means for locating the polymer to be formed at one end of the cavity and means for introducing fluid into the inlet opening of said bore and into the cavity . the apparatus also comprises exhaust means communicating with the exit opening of the bore , so that introducing the fluid through the polymer causes the polymer to assume the shape of the cavity and the fluid forms a hollow channel to define a needle - like structure in the polymer as the fluid is exhausted through the cavity and the bore .