Somatropin is a genetical recombinant natural type human growth hormone preparation, a peptide consisting of 191 amino acids (molecular weight about 22,000).
According to the European Pharmacopoeia (EP 9.5*), analysis of somatropin dimers and high molecular weight related substances should be carried out with a column filled with hydrophilic silica gel, suitable for protein separation in the molecular weight range of 5,000 to 150,000 and meets following requirement. The PROTEIN LW-803 confirmed the requirement was met. In addition, about 5 times better peak/valley ratio was obtained by the LW-803 when compared with other companies' equivalent column, and tetramer was clearly detected.

System suitability requirement:
   The peak-to-valley ratio**: ≥ 2.5

*The version at the time of the application acquisition. 
**The height from the baseline of the dimer to the peak top divided by the height from the baseline of the valley between the dimer/monomer.


Sample : 20 μL
Somatropin 1.0 mg/mL
(pretreated at 50 °C for 24 hours)
1. Tetramer
2. Trimer
3. Dimer
4. Monomer

Columns      : Shodex PROTEIN LW-803 (8.0 mm I.D. x 300 mm)
               Silica-based SEC column from other manufacturer (7.8 mm I.D. x 300 mm)
Eluent       : 2-Propanal/0.063 M Sodium phosphate buffer solution (pH7.0)=3/97
Flow rate    : 0.6 mL/min
Detector     : UV (214 nm)
Column temp. : 25 °C