Only Propylene glycol USP/EP (pharmaceutical grade) is qualified and approved for use as an excipient in pharmaceutical applications as laid down in the respective Pharmacopoeias (USA, EU). These also require regular extensive testing of the product against the USP and EP. In other regions, other Pharmacopoeias may apply as well, for example the JP in Japan and the ChP in China.
The main function of propylene glycol USP/EP (pharmaceutical grade) in pharmaceuticals is to dissolve the active medicines and provide equal distribution of the medicine ingredient in the formulation, so that each pill, liquid dose or cream-based application always contains the exactly prescribed amount of curing agent.
Propylene Glycol pharmaceutical applications include: