Does filtering work? Yep, lab tested....
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@Stevepep I agree. Still, the length of even a long 191 AA polypeptide (HGH) if unrolled in a line is about 67 nm (but it's usually rolled into 5 nm 3D structure), other peptides are much smaller. So even 0.1um (i.e. 100 nm) filter is theoretically fine if it is a low-binding material. Just do it slowly. But those Mycoplasma contaminants also don't scare me too much, it's a minor threat. So, I guess I don't care much either.
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This post is deleted!
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@vpeptides I am no expert in this area and have no care either way what the correct answer is but they both essentially say the very same thing.
tertiary-structured proteins, highly fragile or complex peptide assemblies could theoretically be disrupted
Bottom line people can use whatever filter they want. I have no horse in this race. AI on peptides sucks because much of the generated information is old and wrong and compiled by people like you and I who know enough to be dangerous.
@Stevepep It's a non issue anyway just from a numbers standpoint. A 0.1 micron filter pore can pass compounds with a molecular weight rating of about 1 million Daltons. The larger peptides we use such as GLP's are ~6000 Daltons. Anything bigger than that is no longer a peptide but is a protein (insulin 5800Da, HGH~22000Da, etc). TRT and such are even smaller.
Stripping the peptide from the solution would happen with nylon or cellulosa based filters (these are PES and chemically modified specifically to allow peptides to pass), extreme pressure (why I tell people to take up to 1 min to filter 3ml - not necessary but a safe number), or if the reconstituted solution is clotted (cloudy and I won't use anyway). Also running a bit of bac only through the filter before introducing the peptide "wets" the filter so you aren't using peptide solution to do that, which would waste a small amount.
Hope this helps.
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Good info. Thanks.
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You guys are much more informed than I am on this topic. Curious - if there were mycoplasma (or any other biological contamination) in these lyophilized powders that were destroyed during the lyophilization process, would the remains be considered endotoxins? Is there any filter that will get rid of those? Without damaging the peptides, of course?
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50count@$57.29 +tax,shpg
I placed an order from them but unfortunately they don’t actually have them in stock. They expect to get it in September. I asked them to cancel my order.
denti
Thanks, they did not indicate on my order that it would take that long to receive them.
All of the other vendors I checked actually disclosed that they were resellers for this item. Also, one of the other vendors said it was only a week delay on the order, so maybe it doesn't take two months.
Novatech had the best prices, however, so I may wait it out.If you find someone who stocks them, please let us know.
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I just placed an order here, not sure how long it will take yet. I’ll keep you updated. But they have free shipping. I’ve ordered from them before, not medical related and they shipped quickly.
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@vpeptides - correct. 0.22 µm (220 nanometers) is the standard pore size used for laboratory sterile filtration. Anything else is overkill from a sterility standpoint.
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@vpeptides - correct. 0.22 µm (220 nanometers) is the standard pore size used for laboratory sterile filtration. Anything else is overkill from a sterility standpoint.
@Blueeyedme
Maybe not if the rat's bbb is not intact. -
Ill also add that the concern of mycoplasma does not seem to be of high concern, since it has a very hard time surviving the lyophilization AND rehydration process, not even adding in the 0.9% alcohol we are all using in our BAC water.
@JtCjEfF Great article!
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You guys are much more informed than I am on this topic. Curious - if there were mycoplasma (or any other biological contamination) in these lyophilized powders that were destroyed during the lyophilization process, would the remains be considered endotoxins? Is there any filter that will get rid of those? Without damaging the peptides, of course?
@diannemccann Yes specifically these are designed for sterility and endotoxins and are the best way for a single vial peptide purchaser to deal with S&E if all they have is IPN on a peptide. Cytiva (PALL) 4908-N Acrodisc Syringe Filters Optimized for Scale Up, Posidyne membrane, sterile, 0.2 µm 25mm. .22 is the standard not .1
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@diannemccann Yes specifically these are designed for sterility and endotoxins and are the best way for a single vial peptide purchaser to deal with S&E if all they have is IPN on a peptide. Cytiva (PALL) 4908-N Acrodisc Syringe Filters Optimized for Scale Up, Posidyne membrane, sterile, 0.2 µm 25mm. .22 is the standard not .1
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I wanted to share this in the hopes that others might start sharing more testing info here on Peptide Critic....
I kept seeing people recommending to filter their peps and started doing some research. I found that the .2 micron filters, while good, aren't 100% for bacteria. Granted the bacteria they would miss are very rare and would not be commonly found in lyophilized peptides, but that less than 100% still bothered me.
Considering there has to be a practical and financial limit to the rabbit hole we go down for research peptide safety, and we all have to find our own comfort level with that, I started doing some more research.
I found sterile 0.1 micron filters for about $1 each and decided to go one step further and actually test them. We had a batch of Reta from JEEP that failed sterility at Janoshik. (also note that this is when we found out that Janoshik will allow someone to edit a report to change the company name, batch number, etc after the fact for a small fee. Def a red flag for doctoring "verified" tests at Janoshik).
I sent in two of those vials and two of the 0.1 Micron filters that I found. I had them reconstitute the two contaminated vials and test half of each vial unfiltered and half of each vial filtered. This confirmed for me that filtering (at least with the 0.1 micron filters) is viable and effective. Note I mistyped the MG size as 24mg instead of 34mg doh. Hope this is useful for somebody.
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Nice specific testing. Thanks!
I guess what we don't know with these results is wether the peptide itself survived the 0.1 micron filtration or not.
Btw, I tested the exact same batch, included endotoxins. These came good.
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@kRazy-pep Syringe filters cannot remove endotoxins. Endotoxins require special ultra resolution filter which may filter out entire peptide content leaving it useless for research. Only other way to remove endotoxins is high temp autoclaving. Not sure once endotoxins get into pep API whether they can be removed. The only way is to AVOID letting them in.
Syringe filters can only remove microbial contents and other larger impurities.
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