11.1 Prostaglandins and their derivatives are depicted using the same conventions as those applicable to steroids and terpenes. Long chains are shown as lines at an angle to one another, all terminal groups being shown in full:

alprostadil

ciprostene

enisoprost

doxaprost
The last two are mixtures of epimers in the carbon chain, which can be shown in the manner indicated in section 7.16:
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 doxaprost
This structure is preferred for epimers by the INN Programme
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