Disclosed is a storage stable prostaglandin E group composition which comprises: (a) a prostaglandin E group compound (such as alprostadil)； (b) a (C1-C4)-alkyl (C8-C22) carboxylic ester (such as ethyl laurate)； (c) an N,N-di(C1-C8) alkylamino substituted, (C4-C18) alkyl (C2-C18)carboxylic ester, a pharmaceutically acceptable addition salt thereof, or a combination thereof (such as dodecyl 2-(N,N-dimethylamino)-propionate - DDAIP)； and (d) optionally, a viscosity enhancing agent (such as guar gum)； the composition containing no more than 0.5 percent by weight of a C1-C4 alcohol.
