Ultraviolet Resonance Raman spectroscopy used to study formulations of salmon calcitonin, a starch–peptide conjugate and TGF-β3

Ultraviolet Resonance Raman (UVRR) spectroscopy with excitation at 244 nm was investigated here as a possible useful tool for fast characterization of biopharmaceuticals. Studies were performed on three protein drugs: salmon calcitonin (sCT), starch–peptide conjugate, and transforming growth factor-β3 (TGF-β3) adsorbed onto solid granules of tricalcium phosphate (TCP). Secondary structure of sCT was investigated for solutions of 0.5 mg/mL up to 200 mg/mL, regardless of the turbidity or aggregation states. An increase in β-sheet content was detected when sCT solutions aggregated. UVRR spectroscopy also detected a small amount of residual organic solvent in a starch–peptide conjugate solution containing only 40 μg/mL of peptide. UVRR spectroscopy was then used to characterize a protein, TGF-β3, adsorbed onto solid granules of TCP at 50 and 250 μg/cm3. This study shows that UVRR is suitable to characterize the protein formulations in a broad range of concentrations, in liquid, aggregated, and solid states.

Aggregation of salmon calcitonin monitored by increase in β-sheet content. Presence of traces of ethanol in a peptide-starch conjugate. Detection of 50 mg/cm3 TGF-β3 adsorbed onto TCP granules.Figure optionsDownload high-quality image (153 K)Download as PowerPoint slide