The present invention relates to a novel prostaglandin derivative having an alkynyl group in the ω chain, in particular, a novel prostaglandin derivative having a double bond at the 2-position and an alkynyl group in the ω chain, and a medicament containing the compound as an active ingredient.According to the present invention, the compound represented by formula (1) or a pharmaceutically acceptable salt thereof, or a cyclodextrin inclusion compound thereof, and a medicament containing the compound as an active ingredient, particularly a medicament for preventing or treating blood flow disorder caused by spinal canal stenosis or chronic arterial occlusion can be provided.Wherein each symbol is as defined in this specification.本發明係關於ω鏈具有炔基之新穎前列腺素衍生物，尤其是於2位具有雙鍵，於ω鏈具有炔基之新穎前列腺素衍生物，及含有該化合物作為有效成分之醫藥。若依照本發明，可提供式(1)： [式中之各記號係如本說明書中所定義]所示之化合物或其藥學上容許之鹽，或彼等之環糊精包接化合物，及含有該化合物作為有效成分之醫藥，尤其是伴隨脊柱狹窄症或慢性動脈閉塞症之血流障礙的預防或治療用醫藥。
