A study of the chemical and biological stability of vasoactive intestinal peptide

Context: Vasoactive intestinal peptide (VIP) is a linear cationic neuropeptide composed of 28 amino acids. It belongs to the glucagon/secretin family. The biological functions of VIP are relatively broad, but it has not been well studied in the field of pharmaceutics. Especially in the selection of the way of VIP administration and the pharmaceutical formulation, the theory basis was deficient appreciably.Objective: To provide the theory basis for the pharmaceutical development of VIP, the chemical and biological stability of VIP was studied. Materials and methods: The stability of VIP in different pH values, ionic strength, temperature, artificial gastric fluid and artificial intestinal fluid was investigated, and the concentration of VIP was calculated by HPLC method.Results: The stability of VIP was pH-dependent. VIP was stable in acid and neutral solution, and almost didn’t degrade during pH ≤ 7 solution. However, it was instability in basic solution and degraded completely at 30 min in pH 13 solution...