May 12, 2025, 01:35:32 AM
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Look, I'm a chemistry guy, not biology.  But industry has a number of specs on bio.  You might check the USP, as a start.  None of what was mentioned sounds familiar.
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Hi, I'm neither a chemist nor a chemistry student. I'm just a curious reader who likes to know about the science of everyday products.

Basically, I read this paper where it says 5% BPO is more appropriate for wash-off formulations because a 100% reduction of the C. acnes isolates was achieved in 30 s whereas 2.5% needed 15 min.

But, if you look at the numbers, 2.5% BPO achieved 93.4% in 1 minute. And this is why I'd like to know your opinion whether their conclusion is accurate.

I don't think it is really more appropiate for two reasons. But first, let's pretend BPO permors the same in vivo and in vitro, without having the in vivo problems of having to get trough skin pores, etc. The two reasons are:

First, BPO treatments aren't usually taken just one day. They're usually taken for weeks and even months. So I think in 1 month of treatment the reduction of bacteria would not differ much between 2.5% and 5%.

And secondly, the study assumes the active stops working once the product is washed off. But cleansers for example are able to deposit BPO so that it continues working even after rinsing.

The study is this one: https://pmc.ncbi.nlm.nih.gov/articles/PMC8922035/

What do you think?

PS.: I put this in the "other sciences" section because I didn't know if this belongs to biology chemistry (due to the bactericidal effect of BPO) or chemistry engineering (due to wash off formulations being able to deliver actives).
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Organic Chemistry Forum / Re: Tsantsa
« Last post by Borek on May 07, 2025, 02:57:28 AM »
I guess you wanted to ask some question about the reaction, but you didn't.

Just in case: please read the forum rules. You have to show your attempts at answering the question to receive help.
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Organic Chemistry Forum / Tsantsa
« Last post by Tsantsa on May 06, 2025, 11:05:34 PM »
TIA

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Chemical Engineering Forum / Re: iso tank crash
« Last post by RomanKatz on May 06, 2025, 04:04:31 AM »
It was washed by a water jet, I am not sure how hot it was. A worker washes it from inside. They do it all the time so i don't think they have used some solvent.
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Chemical Engineering Forum / Re: iso tank crash
« Last post by Borek on May 06, 2025, 03:12:00 AM »
If it was shut tight, it could implode, quite popular experiment.

What was it cleaned with? Was it hot during washing/cleaning? It doesn't have to be boiling water, perhaps it was washed with some low boiling, organic solvent?

https://www.youtube.com/watch?v=JsoE4F2Pb20
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Chemical Engineering Forum / iso tank crash
« Last post by RomanKatz on May 06, 2025, 02:44:44 AM »
Hello friends,
we have encountered a strange event. At the plant there is an iso tank washing station. According to them, the tank was washed and cleaned, awaiting clearance when it suddenly collapsed within itself, like a vacuum from inside. How can this be?

See a pic


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Inorganic Chemistry Forum / Re: How do they make H2S sniffing sticks?
« Last post by Borek on April 29, 2025, 02:09:15 PM »
Yes, H2S is highly toxic and dangerous. My bet is these test sticks are made in such a way they don't contain enough sulfur to be dangerous (which is actually another reason why they can be difficult to replicate).
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Inorganic Chemistry Forum / Re: How do they make H2S sniffing sticks?
« Last post by Hunter2 on April 29, 2025, 11:51:58 AM »
H2S is like HCN in power of poisson.
Danger is in high concentration  you cannot smell it anymore cause deadly accidents.
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Inorganic Chemistry Forum / Re: How do they make H2S sniffing sticks?
« Last post by marquis on April 29, 2025, 10:44:54 AM »
Definite issue of concern with H2S.  We used H2S for heavy metals testing per the USP.  Always did it under a hood. But still...The issue of not being able to smell it if it got to strong always bothered me (and hopefully others)..
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