Buldge during IP - (Mar/02/2011 )

Hi,
Sometimes (not always) while IP injection, I get a slight buldge under the skin of the mice. It eventually subsides. It is something to worry about?

bsp237 on Thu Mar 3 01:46:01 2011 said:

You seem to have problems with injecting. Dont you have someone to help you? Its very hard to tell you what might cause this. (or show you how to inject?)
It could be air but it could be an internal bleeding (or loss of some blood), it could be nothing (that you think itsn a buldge, but that its just the skin that "pops out" because you put tension on it).
Or maybe you just feel the needle itself? Its hard to tell.
Or maybe the buldge is nothing more then the fluid you inject.. its hard to tell really.

My guess is that you are not actually doing an IP injection but a subcutaneous injection. You should not see a bulge after an IP injection, but you would see one after a SC injection. You may not be putting the needle in far enough prior to injecting. You should have someone who has done a lot of IP injections watch you to ensure that you are at the proper depth. This is important because there is quite a bit of difference between the rate of absorbance between IP and SC (where IP is much faster). If you are injecting a drug with a fairly short half-life in the animal, this can make a very big difference.

MM