Why were micronutrient supplements like Micronutrient Powder (MNP) developed?

It was observed that the standard iron drops were not effective, as adherence to treatment remained poor. A simple, inexpensive and potentially viable new method to provide micronutrients was conceptualized. Responding to the challenge, micronutrient supplements (with different brand names) were developed. "Sprinkles" was the first brand developed by the "Sprinkles Global Health Initiative" at The Hospital for Sick Children, University of Toronto.