We receive a prescription from a GP with following Magistal preparation: isosorbide dinitrate 1g in PEG solution 100ml? How do I start?

Isosorbidenitate is used for the local treatment of the use of the oral fissures. I suspect that the doctor would like to use a different ointment base here and mean PEG ointment. Perhaps he speaks of solution because this ointment is a mixture. I do not see well in what advantage a liquid preparation would give; The adhesion to the injury to be treated will also be little efficient.