Forum freeze-drying.eu

[Lal]

Hi Folks,

I am new to this forum as well as to freeze drying.

Recently purchased a Lab scale freez dryer and would like to set up some test runs.

Questions about primary drying cycle.

* Tg' for the product is -29C
* Shelf temp: -35C
* 2ml sample (12 ml vial)

How should a typical primary drying cycle look like? especially the begining and the end before it moves to secondary drying phase?

* -35C: 100mtorr: 20h
followed by gradually raising the temp to 20C (?) i.e
* 0C: 100mtorr: 1h
* 20C: 100mtorr: 1h (end of primary drying?):

Enter Secondary drying.
* 20C:50mtorr:6h

[ramshanpharm]

Hi,
Welcome to the board
Prior to answer your question, I would like to have some more information, which I feel important to decide the drying cycle (both Primary as well as Secondary),
What's the nature of formulation composition you intend to lyophilize?
Have you taken any batch with the said recipe? If so what was the fate of final product? (Like Physical appearances, Reconstitution time & Quality)

Regards,
Ramesh Kumar
_________________
If you fall-down, try to get something while you get-up.

[Lal]

Hi Ramesh,

The formulation contains subunit vaccine. The compostion is essentially sugars, polymers and surfactants. The cycle which I used was the manufacturer set cycle for proteins.
The product/cake looked fine in appearance (no shrinkage or phase separation), however it does not dissolve very well. Took > 0.5 h (no physical agiagtion) to dissolve.

i am not clear about the steps after 20h @ -35C in the primary drying phase. Should it be gradually ramped up to teh set temperature (20C in this case)?

Thanks,
[/u]

[ramshanpharm]

Hi,
From your mail it's clear that, you are not using any kind of crystalline agent/s in your indented formulation composition: (correct me if i am wrong )

So, you can follow conservative primary drying approach instead of normal one. Try with -15C or -10C step depending upon your product temperature at the end of -35C, 20h. Check moisture content at the end of each step during primary drying by any of methods you (and/or your equipment) are comfortable with (like PRT).

I can suspect following parameters in your formulation: Probably your product contain more moisture content (so check with that )
Why you are using 12 ml vial for 2 ml sample (instead you can go for 5 ml vial and check the same)
What's the final moisture content of your product?
So try with this & feel free if you need further clarity regarding the same .

Regards,
[i][b][color=green]Ramesh Kumar[/color][/b][/i]
_________________
If you fall-down, try to get something while you get-up.