Why is pharmacy-grade potassium permanganate unsuitable for chemical synthesis or oxygen generation?

Why is pharmacy-grade potassium permanganate unsuitable for chemical synthesis or oxygen generation?
Pharmacy-grade potassium permanganate tablets are legally sold over-the-counter in China as a common disinfectant, but they are not pure chemical reagent. These tablets contain pharmaceutical excipients such as boric acid and low-substituted hydroxypropyl cellulose, which are organic compounds. While the diluted solutions work fine for qualitative tests of reducing agents, heating the crushed tablets to generate oxygen is dangerous. The organic excipients can react violently with potassium permanganate under heat, potentially causing combustion or even explosion. Potassium permanganate is also classified as a Category III precursor chemical and an explosive-prone hazardous chemical, though personal small-quantity purchases for medical use are exempt from registration. Industrial buyers must source pure grade material from licensed chemical suppliers, not pharmacies.