https://www.selleckchem.com/products/nvs-stg2.html This article is protected by copyright. All rights reserved.RATIONALE For pharmaceutical quality control, impurities may have unexpected pharmacological or toxicological effects that seriously impact on safety and efficacy. Arginine vasopressin (AVP) is an important cyclic peptide drug, which is mainly used for the treatment of diabetes insipidus and esophageal varices bleeding. With the improvement of analytical techniques, liquid chromatography-high resolution mass spectrometry (LC/hrMS) has become a critical technique for the challenging task of the. identification and quantification of peptide impurities structurally related to AVP. METHODS An LC/hrMS/MS-based method using a quadruple ion trap-Orbitrap mass spectrometer operated in positive ion ESI mode was developed for the determination and quantification of structurally related peptide impurities in AVP. RESULTS Under optimized experimental conditions, 3 deamidation products, ([Glu4 ]AVP, [Asp5 ]AVP and AVP acid), 2 amino acid deletion impurities (des-Pro7 -AVP and des-Gly9 -AVP), 1 amino acid insertion impurity (endo-Gly10a -AVP), 1 end chain reaction product (N-acetyl-AVP) and 1 AVP isomer were detected. Subsequent quantification using an external standard method allowed the total mass fraction of all structurally related peptide impurities in the AVP study material to be estimated as 30.3 mg/g with an expanded uncertainty of 3.0 mg/g (k=2). CONCLUSION This work complements the AVP impurity profile and facilitates improved separation and discovery of other potential impurities in vasopressin analogues. This article is protected by copyright. All rights reserved.BACKGROUND Compounded preparations (CPs) are an indispensable addition to approved, commercially available drugs (CADs), especially for topical therapy. In Germany, about eight million CPs are prescribed within the statutory health insurance system each year, 50 % thereof by dermatologists. METHODS W