Fast separation of bacitracin on monolithic silica columns

Pathways of Chemical Degradation of Polypeptide Antibiotic Bacitracin

“…21,22) As found by our experiments the favoured pathway of degradation of Bc stored at elevated temperatures in neutral water solutions is oxidation (Fig. 2).…”

“…column which dramatically reduced analysis time. 21) In the present paper we more clearly confirmed the pathway of Bc (ZnBc) oxidation by performing additional stress tests on its isolated microbiologically active components. Non-oxidative desamido degradation products of Bc formed by deamidation of free amide group of AA L-asparagine are mentioned in publications even less frequently than oxidative ones.…”

“…1). 21,22) In several papers on HPLC separation of Bc carried out up to the present we frequently pointed out that under certain experimental conditions (especially when mobile phases with lower pH were used) the peaks of degradation products may be asymmetric or may even split into two subunits (e.g. F splits into FЈ and FЉ).…”

“…The study of decomposition mechanism in such systems is tricky and often unsuccessful due to numerous possible interferences. In order to firmly establish and confirm the major degradation pathways we isolated microbiologically active components of Bc (A, B1, B2, B3), their oxidative degradation products (H1, H2, H3, F) 21) and hydrolytic desamido degradation products (Xa1, Xa) of BcA. The isolation was done with a preparative HPLC.…”

“…6) In our recently published HPLC method for Bc, the mentioned oxidative degradation products H1, H2 and H3 were chromatographically clearly defined for the first time. 21,22) We used mainly the new type monolithic silica reversed-phase Chromolith RP-18e (100ϫ4.6 mm I.D.) column which dramatically reduced analysis time.…”