Stability of sfti dbf in pooled human serum

Stability of SFTI-DBF in pooled human serum (Innovative Research, Inc, Novi MI) was analyzed for 24 h. 2 mM stock solution of the peptide was prepared in PBS, and 150 μl of the stock solution of the peptide was incubated with 1350 μl pooled human serum in the ratio of 1:9 as described previously.^{15 (link)} At each time point, 150 μl of the solution was taken, and the enzyme activity was terminated by adding ice-cold acetonitrile and was centrifuged at 10,000 rpm for 10 min. The supernatant was passed through a Sep-Pak column (Waters) and lyophilized. Freeze-dried samples were reconstituted with 300 μl of acetonitrile: water (50:50) and analyzed by HPLC (Shimadzu) for change in peptide peak intensity.