INJECTABLE COMPOSITION COMPRISING GNRH DERIVATIVES

An injectable composition of the present invention has remarkably increased safety by forming, into a composition, a sorbitan unsaturated fatty acid ester comprising g a polar head group with two or more -OH (hydroxyl) groups, is in a liquid phase in a phase where an aqueous fluid is absent so as to be easily applied to pharmaceutical preparations in dosage forms, and forms a liquid crystal in an aqueous fluid phase so that sustained-release effects of GnRH analogue, which is used as a pharmaceutically active substance in vivo, are exhibited. In addition, in an injectable composition of the present invention, a sustained-release lipid initial preparation comprising GnRH analogue includes water, and thus a liquid injectable agent forms a liquid crystal gel immediately after administration, so that the effects of reducing initial release rate and remarkably increasing sustained-release properties of the drug are exhibited.