Provided is an injectable drug carrier including a non-toxic Layered Double Hydroxide (LDH) and pharmaceutically acceptable excipients. Provided is also a method of preparing the injectable drug carrier, the method including: synthesizing LDH with various compositions and controlling the size and shape of the LDH at a level that the LDH has no adverse effect in vivo. A solution obtained by dispersing the LDH in a solvent is injected in vivo. According to the method, nano-size LDH that does not affect a blood vessel in vivo can be synthesized. The LDH thus synthesized has no adverse effect in vivo even at a concentration of 400 mg/kg, and thus can contribute to establishment of a drug delivery system capable of improving the delivery efficiency of a specific drug.