RP-HPLC purity, mass spectrometry, appearance and lot control for PT-141.
Appearance and identity
Reference lots are typically a white to off-white lyophilized powder. Mass spectrometry confirms identity against the average mass (~1025.2) calculated from C50H68N14O10, and can help verify the intact cyclic structure expected of the standard.
Purity by RP-HPLC
Reversed-phase HPLC on C18 columns with acetonitrile/water gradients and acidic modifiers is the standard purity assay. Method development focuses on resolving the cyclic peptide from any linear precursor and process impurities; reference grade is specified at ≥98% HPLC.
Lot control
Documentation generally includes HPLC chromatogram, MS confirmation and appearance. Monitoring counter-ion and water content supports accurate quantitation, and consistent cyclic-purity assessment is key to lot-to-lot reproducibility for receptor-binding reference use.