Embodiments relate to a cannula that is provided for delivering a substance, such as a medicine (e.g., insulin) to a patient, where the cannula has reduced likelihood of kinking or occlusions when implanted in a patient. The cannula may have a reduced number of stress concentrations along its length, an angled tip and/or a curve in its length. The cannula may include other designs to reduce kinking, such as internal ribbing and/or a slit along its wall.
