A system and method is provided for an injectable substance delivery pen comprising a microneedle hub assembly removably engaged with a pen device body which includes a cartridge, a plunger, and a drive mechanism. The hub assembly includes at least one microneedle for intradermal or shallow subcutaneous injection of the contents of the cartridge. The cartridge, plunger and drive mechanism components of the pen body are fabricated of non-compliant and non-compressible materials to allow effective communication of the cartridge contents via the microneedle patient interface.