c has the same peaks as USP Insulin, however, it has fewer contaminants Related Substances R & D Insulin Drug Substances Identity Retention Time F'eak Area Relative Area % Insulin • 21.19 • 884.701 • 99.11 A5/B4 Desamido • • 22.96 26.3 • • 0.842 0.508 • • 0.11 0.07 A21 Desamido •