in trouble

[amrit]

i am involved in the stability and compatibility study of Imipenem and Cilastatin. For a couple of months i am wasting my time in LC-MS stability indicating method development for the same. My aim will be to develop the stability indicating method, which will well separate drugs as degradation products of the both drugs formed during different stress conditions, like acidic, hyydrolytic, oxidative, photolytic etc.

second thing is i have to LC-MS bioanalytical method for the same, so volatile buffer is essential.

then i moved to volatile buffers, first tried ammonium acetate, at pH of above adjusted with ammonia or acetic acid,

lastly i tried formate buffer, again results were disgusting, there is not a single LC-MS method for the drugs reported in literature.


lastly i landes with the 25mM ammonium acetate and ACN method, again bad peak shape, surplus tailing and two peaks of fresh sample not being separated at base line of IMIPENEM.

i am using supelco discovery C-18 column., Brucker Daltonics LC-MS-TOF with Agilent HPLC
too much frustrated till now

i would appreciate your suggestion that could help me in casting the proper way further

[amrit]

this imipenem has been nuisance for me for a longway. i think i have to turnout of my project. i never suceeded to develop its analytical method