Freezing BAC water

[stickfigure]

Water and benzyl alcohol have different freezing points. When freezing, water will freeze first at 0°C, forming ice on top of the vial because ice is less dense than water. Once all the water has frozen, it will consist of ice crystals floating in liquid benzyl alcohol. Then, at -15°C, the benzyl alcohol begins to freeze, following a similar pattern as the water. Although they separate during freezing, they will easily mix back together once thawed. There is nothing in the ice crystals that could damage the liquid benzyl alcohol. Below -15°C, two types of crystals will form in the vial: frozen water and frozen benzyl alcohol.

The molecular bonds of water and benzyl alcohol are much stronger than those of ice crystals, so ice cannot damage the molecules.

The biggest risk is the pressure from the expanding water, which could crack the plastic vial. That's why I was asking if anyone has had success with this. I’m not concerned about the vial’s contents surviving freezing—science indicates that the contents will actually be much more stable when frozen.

However, if the ice pushes air out of the vial during freezing, there is a chance outside air will be drawn in during thawing, which could introduce bacteria. This is a serious concern for anyone using bacteriostatic water (BAC) as is. In my case, though, I am filtering the reconstituted peptide with a syringe filter, so any bacterial contamination will be addressed during filtration.

 

[scarywood75]

Water and benzyl alcohol have different freezing points. When freezing, water will freeze first at 0°C, forming ice on top of the vial because ice is less dense than water. Once all the water has frozen, it will consist of ice crystals floating in liquid benzyl alcohol. Then, at -15°C, the benzyl alcohol begins to freeze, following a similar pattern as the water. Although they separate during freezing, they will easily mix back together once thawed. There is nothing in the ice crystals that could damage the liquid benzyl alcohol. Below -15°C, two types of crystals will form in the vial: frozen water and frozen benzyl alcohol.

The molecular bonds of water and benzyl alcohol are much stronger than those of ice crystals, so ice cannot damage the molecules.

The biggest risk is the pressure from the expanding water, which could crack the plastic vial. That's why I was asking if anyone has had success with this. I’m not concerned about the vial’s contents surviving freezing—science indicates that the contents will actually be much more stable when frozen.

However, if the ice pushes air out of the vial during freezing, there is a chance outside air will be drawn in during thawing, which could introduce bacteria. This is a serious concern for anyone using bacteriostatic water (BAC) as is. In my case, though, I am filtering the reconstituted peptide with a syringe filter, so any bacterial contamination will be addressed during filtration.

Yeah I don't agree, otherwise Hospira will suggest to freeze it if it were to be better, heck they don't even suggest to put it in the fridge

I would think a multi billion company knows better than us how to store their product

 

[stickfigure]

You are welcome to fact check my statements using your favorite LLM (including ones indexing scientific literature) or any other sources.

I've told you why Lilly would not suggest freezing - potential bacterial contamination on thawing and liquid separation - someone could draw pure benzyl alcohol if the vial is between 0 and -15 C, which would not be good. Both are valid concerns, but not for my use case, as explained in detail above.

 

[nurseratchit]

Sounds like you already have your plan in place so not sure why you posed the original question. Good luck to you.

 

[stickfigure]

I've asked if anyone had bad luck with plastic vials cracking. I don't want to find out that my doomsday supply is ruined when I need it. But I've frozen a couple test 30ml vials. I've decided to be extra cautious and froze it to -18 first to relieve stress while plastic is not yet too brittle. I will continue to -80 once they spend a few days at -18.

 

[Labcat]

I've asked if anyone had bad luck with plastic vials cracking. I don't want to find out that my doomsday supply is ruined when I need it. But I've frozen a couple test 30ml vials. I've decided to be extra cautious and froze it to -18 first to relieve stress while plastic is not yet too brittle. I will continue to -80 once they spend a few days at -18.

Hi, @stickfigure ! I was pointed to your thread because I was asking some related questions! Did you every try freezing your BAC?

You might have found out that plastics like the vial (proplyene and ethylene copolymer) freeze well down to -20C, sometimes-40C. So it probably can be fragile at -80C.

The mdv stoppers are typically a butyl rubber and stay flexible down to -40C ish.

I agree with your science about the stabiliy of the benzyl alcohol to freezing and how the mix will need gentle reintegration and full melting before use. You might try freezing at -20, regular inexpensive deep freezes easily reach that.

You can also consider recon using sterile water in future if needed. Autoclaving will remain available. Benzyl alcohol is also commonly available usp grade and sterile, that might be our best bet in a shortage situation, (hey, iv saline has been in shortage on and off for years, our system is very broken.) or maybe we should look onto how to recon with phenol since so many compounders do it,

I’d love to know what you found out, and appreciate seeing your technical explanations.