This happened when I tried to freeze-dried Vancomycin that I want to recover from my experiment (in water). I tried precipitating the product in water-miscible solvent that Vancomycin are not soluble in (e.g. Acetone). The precipitation was white, and came after a while. It was quite ineffective as a lot of Acetone is needed.
However, the product (after possible removal of impurities) after freeze-drying turned into a web-like fiber, kinda like cotton. It looks fluffy, but the product collapsed when I squeeze it so the inside seems to be an empty and flexible porous structure. When I tried to re-dissolved in water, it does.
At first I thought it's because of the impurities that I might have failed to remove, but when I tried freeze-drying from fresh Vancomycin in water, it turned out the same. At first I thought that it's not dry, so I left it for 3 days but the result is the same.
I then tried it with a Vancomycin Nanoparticle (PLGA) and free-base Vancomycin (pH 8) but surprisingly, it actually turned into powder.
My guess was that there might be an interaction between the drug itself (at the Amine group) that help formed this or due to its large structure (but the MW of 1.4k is low).
Anyone know why this happen? Is it a normal problem in freeze-drying? I've read about difficulties encountered with sugar and fruit-like products but it doesn't seem to be the case here.
Yes, I have freezedried (FD) my samples (starch). It gives a spongy structure too. The texture/structure entirely depends on the nature of the samples. If it is well dissolved in water, the structure of FD samples is usually sponge-like. However, if it is undissolved (dispersion), the original structure tends to retain usually. This may indicate the samples have no major interaction when they are in the water as medium.
Hello Panarin
I, also freeze dried my sample and get the spongy structure too. freeze drying is one of the best method of drying for heat sensitive and high quality product as it does not affect the property of material. because
freeze drying or lyophilisation is a process of water removal from a product after it is frozen and placed under a vacuum, which allow the ice to change directly from solid to vapor phase without passing through a liquid phase.
so, frozen water removed throughout the material and leaving behind the intact solid material which give a spongy or fluffy structure. you can further grind it to get a fine powder.
Dear all,
I have not had the proper time to thank you all for your answer. Please forgive my lateness. Thank you everyone.
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