Secretin has molecular formula of C130H220N44O41,a.a. sequence of H-His-Ser-Asp-Gly-Thr-Phe-Thr-Ser-Glu-Leu-Ser-Arg-Leu-Arg- Asp-Ser -Ala-Arg-Leu-Gln-Arg-Leu-Leu-Gln-Gly-Leu-Val-NH2 and having Mw of 3055.4 Dalton. 1 * 25 mg