Benzocaine stock solution

[taraegan]

Hi all,


I'm in the process of reviewing our zebrafish documentation and I have a query about benzocaine stock solution. How long after preparing the stock solution should it be discarded? Any other tips and recommendations around storage/handling of benzocaine would be much appreciated.


Thanks,
Tara

[bruce]

Hi Tara,
We mix our benzocaine solution up in small batches of no more than 100ml at a time.
Our target is to provide quantities we are likely to use within 3 - 4 months.We don't specifically have an expiry policy on our stock solution because of this.
Given that the base materials are relatively cheap, if you were to dump 20 ml or so it's not going to cripple the budget.
We store at room temperature in sealed schott bottles wrapped in alfoil to keep the light out.

Try and use a fume cupboard when you're working with the dry powder.
I've found it to be pretty robust generally when you're using it in high dosages as a terminal agent.
Our process is always to start a little low when we are looking at a surgical plane dose rate.
If there is a bit of variation between batches then it gives you a little bit more reaction time.
It's easy to add a little more if you are finding loss or caudal reflex takes too long.

[Tara]

Thanks for the advice, Bruce. Another quick question around dosing for euthansia....we have been adding 2ml of stock solution per L for euthanasia but query whether you think it is better to opt for closer to 10ml stock solution and potentially a more rapid death. What's your opinion on this?

Thanks again,
Tara

[bruce]

Hi Tara,
I guess it does depend on your stock solution concentration and a few other factors we haven't defined.

Our current protocol is 600mg / Litre.
We have found that to be very rapid and doesn't carry huge excitation response.

So I guess depending on the strength of your stock solution, we may be considerably higher than you?
I wouldn't see much benefit in going higher than 600mg.
at 600mg you will see loss of righting < 1 minute.