 Cleavage of the caproate ester of gestonorone caproate is minimal, which indicates that it is not a prodrug of the unesterified steroid.Gestonorone caproate, also known as norhydroxyprogesterone caproate, 17α-hydroxy-19-norprogesterone 17α-hexanoate, or 17α-hydroxy-19-norpregn-4-ene-3,20-dione 17α-hexanoate, is a synthetic norpregnane steroid and a derivative of progesterone.It is specifically a combined derivative of 17α-hydroxyprogesterone and 19-norprogesterone, or of gestronol (17α-hydroxy-19-norprogesterone), with a hexanoate (caproate) ester at the C17α position.