in vitro use of injection form of drugs - (Mar/23/2005 )

Hi! I would like to ask someone, who have experience with glucocorticoid dexamethason or some other drugs. Is it possible to use injection form of drug for in vitro experiments? We use injections where dexamethason is in form of dexamethasonii natrii phosphate, I know that this form should have better solubility, but can other substances such as vehicles influence efect of dexamethason, if used in vitro? Does it have to activate in blood plasma, or it doesn't really matter if I use injection instead of pure dexamethasone? And where else could possibly be a problem when I observe effect at very high concentration while other authors report effect in much lower concentration, using same cell line, of course.
I would really appreciate any help.
Thans

hi
this topic may help you for a part...

http://www.protocol-online.org/forums/inde...?showtopic=5156

Thank you Fred,
that link was interesting, but did not quite solve my problem. I would need to know if I can use injection in vitro,or if it is possible to use it only in vivo. Because my injection dexamethason doesn't seem to work at all, and I can not find the problem.