Storing lyophilized peptides on receipt: what manufacturer storage guidance says

Start with the label and the safety data sheet

The product label and safety data sheet are the storage instruction for your lot; general manufacturer guidance fills gaps. Cayman's Substance P page, for example, gives a storage temperature of minus 20 °C, describes the product as a lyophilised powder, and offers a safety data sheet. [5] Peptides EU's FAQ says to store lyophilised vials cold, at 2 to 8 °C short term and minus 20 °C long term, sealed and protected from light. [6]

This guide covers storage and inventory of sealed material only. It gives no instructions for preparing solutions or using any peptide.

Temperature: what manufacturers state

Manufacturer figures differ slightly, so record the one that applies to your product. Bachem's FAQ says peptides should be kept in solid form in a deep freezer below minus 15 °C for long-term storage and that a refrigerator at plus 4 °C is acceptable short term. [1] Its handling guidelines add that the lyophilisate should be kept in a tightly closed container below minus 15 °C and that lower temperatures are preferred. [2] GenScript says lyophilised peptides should be stored at minus 20 °C, away from bright light. [3]

Shipping at room temperature is normal and does not change the storage instruction. Bachem says its research-grade products ship at ambient temperature unless specified otherwise, that sealed lyophilisates tolerate 1 to 2 days at ambient temperature, and that on receipt the product should be stored at the recommended temperature. [1] Cayman ships its peptide at room temperature in the continental US and notes this may vary elsewhere. [5] Our temperature excursion guide covers what to record if a parcel was delayed.

Moisture: the main risk in storage

Bachem says peptides are often hygroscopic, that adsorbed water may decrease stability and reduce peptide content, and that samples should be warmed to room temperature in a desiccator before opening. [4] Its FAQ adds that short and arginine-rich peptides can be very hygroscopic and should be protected from humidity, and that vials should be resealed right away once opened. [1] GenScript says peptides containing Asp, Glu, Lys, Arg or His should be stored in a desiccator in a tightly capped vial, and to warm the vial to room temperature before opening. [3]

For an inventory, the practical rules are: keep vials sealed until needed, store them in a closed secondary container with desiccant if the label or sequence calls for it, and record every time a vial is taken out of the freezer.

Light and sequence-specific stability

GenScript advises keeping lyophilised peptides away from bright light, and Bachem says peptides should be protected from intense sunlight, with fluorophore-labelled peptides kept in the dark. [3] [1] Bachem also says peptides containing Trp, Met or Cys need special care to avoid oxidation, and that peptides containing Asn, Gln, Met, Cys and/or Trp have limited shelf lives. [2] If your peptide contains these residues, give its retest or expiry date more weight in planning and avoid unnecessary freezer removals.

Turning label statements into freezer-log entries

Each statement on a label or data sheet should become a field someone can check. Our inventory log template has columns for all of these.

Receipt-to-freezer checklist

Use on the day of delivery.

• Record delivery date and time, and the time the vials go into storage. [1]
• Copy the label storage statement into the inventory exactly as printed.
• File the certificate of analysis and safety data sheet for the lot. [5]
• Place vials sealed, in an opaque or carton-protected box, in the stated temperature unit. [3]
• Add desiccant to the secondary container for hygroscopic sequences. [3]
• Set a review reminder before any retest or expiry date.