Isolation and Characterization of Novel Degradation Product of Pidotimod

Abstract

A synthetic dipeptide, pidotimod (3-L-pyroglutamyl-L-thiaziolidine-4-carboxylic acid, PTD) is an immunomodulator and it possesses anti-infective activity against variety of infections. The objective of this study was to explore into and identify pidotimod’s major degradation product. Pidotimod was degraded in ICH prescribed stress conditions. pidotimod was degraded 90% in 1.0 N NaOH at 80 ºC for 6 h and the degradation product (DP2) was determined using HPLC. The HPLC method was used to separate the primary and subsidiary degradation products and carried out on a C18 column with a mobile phase of ammonium acetate buffer (pH 4.5; 10 mM) and MeOH/ACN (90:10 v/v) at a ratio of 97:03 v/v at 40 ºC, flow rate of 1.0 mL/min, and detection at 215 nm. IR, NMR and LC-MS-MS were used to identify degradation product (DP2) as 3,8-dihydroxy-tetrahydro-bisthiazolo[3,4,4a,3′,4′- d]pyrazine-5,10-dione.