Hello

Lyophilization and freeze drying are synonymous. It is a water removal process which works by freezing the particular substance, then reducing the pressure and adding heat to allow the frozen water in the substance to sublimate. So you can either freeze dry or lyophilize. Both mean the same process.

The lyophilized peptide can be dissolved in DMSO by adding DMSO drop wise till the peptide dissolves. Then add deionised water to obtain the desired concentration.

Try not to exceed DMSO more than 0.1% in the final concentration when the peptide solution is to be added to the cells in the cytotoxicity assay. This is because if DMSO is more than 0.1% in the final concentration then it could be toxic to the cells.

Hope this helps

Good Luck.

The yield can be measured by weighing the dried peptide, as long as there is enough of it, on an analytical balance.

Other than lyophilization/freeze drying, you can vacuum dry the peptide with P2O5, (or, other drying materials) if water present is in very small to traces scale. A constant weight dried material weight will provide yield. For your cytotoxic tests, a carrier (solvent) compatible with your test conditions and cell lines or tumor/cancer is advisable. Check few articles on the peptides cytotoxicity test using the vehicle/carrier for the similar cell lines/cancers test. Solubility and non-toxicity of the solvent/vehicle are important.