Choosing Reconstitution Solutions for Lyophilized Peptides

Solvent choice follows the peptide's chemistry: charge and hydrophobicity. Neutral-to-polar peptides dissolve in water; basic peptides improve dramatically in dilute acid; acidic peptides prefer slight basicity; hydrophobic and lipidated peptides may require an organic co-solvent leg. The experimental context adds constraints: assay compatibility, preservative tolerance, and downstream dilution. Every solvent below is a laboratory reagent for in-vitro work.

Sterile water: the clean default for single-use solutions. Bacteriostatic water: sterile water plus 0.9% benzyl alcohol for multi-use stocks (details in bacteriostatic water for lab use). Buffers (phosphate, acetate) hold pH where the experiment demands it. Water grades and their specifications are compared in water types for peptide reconstitution.

Dilute acetic acid (typically 1-10% v/v, sometimes with a salt such as sodium acetate) is the classic solvent for basic peptides: protonating acidic residues adds net positive charge and repels aggregation. For very acidic peptides, the mirror trick is a small amount of dilute ammonia or a basic buffer, which deprotonates the basic residues.

DMSO dissolves hydrophobic peptides that water cannot touch; the standard pattern is dissolution in a minimal DMSO volume, then dilution into the aqueous solvent to a working organic fraction (commonly under 5-10%). Acetonitrile and alcohol play the same role in some workflows. The trade-offs - assay interference, freezing behavior, hygroscopicity - belong in the sample record.

Solvent choice is one input to the full protocol in how to reconstitute peptides; the concentration arithmetic that follows is in peptide concentration calculation. Sequence-specific laboratory references in this cluster — GHK-Cu, Glow, Klow blend — apply the same logic to concrete products.