I need to perform an enzyme inhibition assay. The dye in reaction mixture is PH sensitive. The enzyme activity, because of dye limitation, can only be detected at PH 7.6 (within PH7 to 8).
I am going to test ciprofloxacin as enzyme inhibitor which is according to MSDS insoluble in water but soluble in 0.1N HCl.
If I would use that HCl as solvent, the addition of even 1uL, will change the PH of reaction mixture which is not suitable for dye to emit signals. I would appreciate the suggestions to solve this problem
Thanks!
Use ciprofloxacin hydrochloride. It is soluble in water at 10 mg/ml.
http://cellgro.com/media/upload/file/productinfosheets/new/Ciprofloxacin%20Hydrochloride.pdf
Please note the instructions for dissolving the powder.
Thanks Adam B shapiro,
In that case, Should I expect the PH of solution around neutral?
According to the following page, the pH will be 4-5.
https://webcache.googleusercontent.com/search?q=cache:PUVcIJfzizEJ:https://www.applichem.com/en/shop/product-detail/as/ciprofloxacin-ibiochemicai/+&cd=6&hl=en&ct=clnk&gl=us
The solubility varies with pH and is low at neutral pH, but increases as the pH rises further. See if you can get sufficient solubility for your experiment at pH 8.
It seems reasonable the use of cyclodextrin soluble complex of ciprofloxacin.
(for example) Acta Poloniae Pharmaceutica Drug Research, Vol. 69 No. 4 pp. 719-724, 2012
Thanks Sergey Khomutov,
I am concern about the cyclodextrin may interfere enzyme inhibition assay. The drug may distribute between the binding pockets on enzyme and on cyclodextrin. Hence no total drug concentration would be available for enzyme.
What do you think Sir ?
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