The devices 400, 500 include microneedles 450, 550 that may be separable from the drug delivery devices, control drug release rate and/or direction, or a combination thereof. When the microneedles are separable, a force applied to the drug delivery devices may be effective to penetrate a biological tissue with the microneedles and then to separate the microneedles from the drug delivery devices. The drug delivery devices may be capable of achieving discrete periods of drug release.