Tetrodotoxin, Na⁺ channel blocker (ab120054)

The specific molarity of the citrate buffer used to solubilize TTX (ab120054) is not as significant as the pH of 4.8. You can essentially use the molarity of citrate buffer that will be applicable with your specific study. As a general guideline for a range that can be used you can use 20 mM Citrate buffer. I also found the following paper which may be helpful, which used 1.5 mM citrate buffer, pH 4.8 to dissolve TTX to a concentration of 300 or 500 uM.

http://www.jneurosci.org/content/17/11/4359.full.pdf

The water-soluble TTX citrate ab120055 is not a citrate salt, it is simply TTX that has been dissolved in a citrate solution, and then lyophilized. So, it has the same molecular weight and formula as ab120054, which is soluble in pH 4.8 citrate buffer to 100 mM.

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The following information is published on the datasheet;

Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to 6 months.

Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.

In short, the stability of product should not be affected in a lapse of 6 hours.

I hope this information is helpful to you. Please do not hesitate to contact us if you need any more advice or information.

Despite extensive checking, including the RTECS database, we can find no toxicity data for inhalation (or skin contact) for TTX. In theory, we are not obliged to include any classification for these routes of entry if no data can be found. Obviously, we think it prudent to include the inhalation and skin contact hazards according to our judgement to make sure we give an indication that we believe TTX to be extremely toxic by all entry routes and not just by ingestion. It is worth noting that some suppliers only include the warning: ‘fatal by ingestion, might be irritating to the respiratory tract, might be irritating to the skin’.

If we were to classify TTX as category 1 by inhalation that would preclude the shipment of this material by air as the material would fall outside of ‘Dangerous Goods in Excepted Quantities’. So we have taken the following pragmatic approach:

The oral LD50 for a mouse is 334ug/kg and if this scales directly to a human, then 25mg would kill a 75kg man. If the inhalation route of entry has a similar level of toxicity (not unreasonable since both inhalation and ingestion require absorption through a moist membrane) then we do not sell TTX in sufficient quantities to prove fatal. Furthermore, the inhalation mode of entry requires (for a solid) the material to be in the form of an aerosol (dust or mist) and we feel that supplied as a lyophilised solid (generally stuck to the inside of the vial) then our product, a reasonably high molecular weight (319), low volatility solid is unlikely to be encountered in this form when handled using Good Laboratory Practices.

We believe that our SDS accurately conveys the hazard potential of this product and as it is intended solely for use in a laboratory, by trained personnel the likelihood of exposure to a fatal level is extremely remote.

I contacted the laboratory regarding the difference between ab120054 and ab120055, and they responded that the only difference between these two compounds is that TTX citrate (ab120055) is the water soluble version, which accounts for the difference in price.

Here are certificates of analysis for the product and lot numbers you have been assigned for your orders (PO numer xxxxx, orders xxxxx and xxxxxx).


If there are any problems please do let me know.

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SL 327 (ab120082) and Kainic acid (ab120100) are both produced at >98% purity as determined by HPLC. I am checking which lots of these products have been assigned to you and then I will send the certificate of analysis for these lots.


The TTX is produced at >96% purity as determined by HPLC but we have stocks of this which is of >98% purity and I will again make sure that these stocks are being allocated to you and send the certificate of analysis.


In the meantime if you have any further questions please do not hesitate to ask.