Often, the medicines that they buy are labeled "Not for resale" or that they were a gift from an Arab country.
The PA as well as Arab countries and NGOs send massive amounts of medicine to Gaza, but they do not seem to be reaching the hospitals they are meant for.
The article claims that drugs donated by the Muslim Brotherhood in Egypt are often expired, though.
In previous years Hamas was accused by both individuals and by the PA itself of diverting the donated medicines to their own pharmacies so they could profit from reselling them. This article implies that this is happening now but doesn't quite say it, perhaps because the newspaper had been banned in Gaza for a while and wants to ensure that it is not shut down again.