Johannes, I've been wondering about how many people who would use the service have access to a smartphone, I believe that adult ownership of smartphones in South Africa is 37%. Might it be necessary to describe how pill drop would work at a local level for those without their own smartphone. For example, are there places that people in villages can go to use a smartphone and the associated app if they do not have one themselves? Or is my concern unfounded? Without knowing the cultural context I am just thinking how this would be in my own country where there are some groups of people who are much less likely to own a smartphone, (e.g. the very elderly and the very poor) who would also be the people most likely to need medication. Other than this the idea is coming on nicely. :-)
I think that you might find that users would be reluctant to make details of their saving accounts known to such an interface. To progress the idea it would really help to do some work with people from your target demographic to see what they think. But beware, people over 50 (and even over 60) do not consider themselves as elderly - that is more for the over 80s, so, if you do speak to potential users try to avoid calling them that :-) Good luck.
This is a really interesting idea which I could see being helpful in other communities too. A couple of questions though. How would you ensure that the drivers delivered the medicine to the patient. I imagine that with some medicines there is a small risk that the medicine could be taken by an unscrupulous driver. Would you have some kind of vetting systems at registration and subsequently the ability to review and award points for trustworthiness etc? Also, would the app allow patients to reserve medication, to ensure that it was available when the driver came to pick it up (with medication in high demand this might be needed). Good luck with the development of the idea.