Hi glitterandlace,
Papaya leaf powder ( not to be confused with green papaya fruit powder ) is available by online order through the internet, so it is widely available nowadays. However, I do believe the papaya leaf powder is available on special order through your local health store.
Here is a link that will provide you with various sources which supplies the papaya leaf powder:
CLICK HERE
You may want to talk to your local health store and tell them of the source, and they may get it for you.
If you read the report in the medical journal carefully, the papaya leaf powder was made into a suspension in palm oil before being used.
Also remember to look into shark liver oil as a means of raising platelets... there is a whole lot of literature on this as well.
All the best,