Stability FAQ¶
1. How is long-term stability determined?¶
Stability studies are conducted per ICH Q1A(R2) guidelines. Batches are stored at -20°C (long-term), 2–8°C (intermediate), and 25°C/60% RH (accelerated) conditions. Samples are tested at defined intervals for purity (HPLC), appearance, water content, and other quality attributes.
2. What degradation pathways are most common?¶
| Pathway | Affected Residues | Byproducts | Prevention |
|---|---|---|---|
| Oxidation | Met, Cys, Trp | Methionine sulfoxide, disulfide scrambling | Nitrogen atmosphere, light protection |
| Deamidation | Asn, Gln | Aspartic acid, iso-aspartate | pH 4–6 optimal, low temperature |
| Hydrolysis | All peptide bonds | Smaller fragments | Lyophilized state, < 1% water |
| Dimerization | Cys, reactive side chains | Covalent dimers | Low concentration, reducing agents |
| Aggregation | Hydrophobic regions | Soluble/insoluble aggregates | Avoid vortexing, gentle reconstitution |
3. What is the recommended shelf life for lyophilized peptides?¶
Under recommended storage conditions (-20°C, desiccated, light-protected), lyophilized peptides maintain ≥95% purity for 24–36 months. Specific stability data is available per product in the Technical Data Sheet.
4. How long is reconstituted peptide stable?¶
| Storage Condition | Typical Stability |
|---|---|
| -20°C (single-use aliquots) | Up to 6 months |
| 2–8°C | 30 days |
| Room temperature (25°C) | 24–48 hours |
| Repeated freeze-thaw | ≤ 3 cycles |
5. How does pH affect peptide stability?¶
Optimal pH range is 4–6 for most peptides. Acidic pH (< 3) accelerates hydrolysis; basic pH (> 8) promotes deamidation and racemization. Always use buffered solutions (PBS, acetate, or citrate) for reconstitution when precise pH control is required.
6. Does RPL Peptide provide stability data for individual products?¶
Yes. Accelerated and real-time stability data is available for each product. Specific stability-indicating methods are used to monitor degradation products. Contact technical support for batch-specific stability data.
For stability-related inquiries: [email protected]