Lyophilisation has three stages. The solution is frozen; in primary drying the pressure is lowered so that ice sublimes directly to vapour; in secondary drying the temperature is raised to remove water still bound to the solid.
Peptides are supplied lyophilised because the dry solid is far more stable than a solution. The product is often a porous "cake" whose look varies between lots, from a compact plug to a loose powder, depending on fill volume and drying conditions; appearance alone says little about quality.
A lyophilised solid still holds some water, which is why water content is measured, and why it should be kept dry and cold.
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For in vitro laboratory research only. Not for human or veterinary use. This library describes chemistry, analytical methods and published laboratory research; it gives no guidance on use in people or animals.