Although I have never prepared ketamine for injection and I'm not sure if the demands are different for that (I would suggest only injecting ketamine that is already in flacons for pharmaceutical use, brand named ketamine such as ketasol, nimatek, ketanest etc. etc. since that is absolutely sterile, even if your water is sterile how do you know you can trust your ketamine?) I have dissolved it in water before and in my experience it does easily dissolves in cold water only I stick with my 'isn't it a better idea to wait until you find yourself pharm grade ketamine ment for injections instead of powdered / crystal ketamine?