TB-500 Storage, Reconstitution & Stability Reference

Sealed lyophilized TB-500 is stable at −20 °C for 24 months protected from light and moisture. The hygroscopic powder should be allowed to equilibrate to room temperature (sealed) before opening to prevent atmospheric moisture condensation.

Freely soluble in water at >20 mg/mL. Recommended diluents: bacteriostatic water, sterile water for injection, or phosphate-buffered saline (pH 7.4). The peptide reconstitutes within 60 seconds; do not vortex aggressively.

TB-500 contains a single methionine residue (Met6). This is the most labile residue and primary degradation site. Air-saturated solutions develop measurable Met-sulfoxide within 7 days at 25 °C. Mitigations: (a) reconstitute under nitrogen-purged conditions where possible, (b) store reconstituted solution at −80 °C, (c) avoid >3 freeze-thaw cycles.

In bacteriostatic water at 2-8 °C: >95% intact peptide for 14 days. At −80 °C aliquoted: >12 months. At 25 °C: ~10-15% loss to Met-sulfoxide over 14 days. The sulfoxide is detectable by HPLC as an earlier-eluting peak (Δt ≈ 2 min on a C18 column).

Up to 3 cycles: minimal purity loss. 5+ cycles: cumulative Met-sulfoxide and minor backbone hydrolysis. Single-use aliquots strongly recommended.

All stability claims reflect in-house analytical lots. COA shipped with every order documents the specific batch's HPLC purity and ESI-MS identity.