Gradient reversed-phase high-performance liquid chromatographic separation of paldimycin (U-70, 138) antibiotics and related compounds

Paulomycin (I in Fig. 1) is a mixture of antibiotics produced by Streptomyces paulus and effective against several strains of gram positive bacterial. Paldimycin (U-70,138) is the bis-N-acetyl-L-cysteine derivative of paulomycin* and is isolated as the trisodium salt (U-70,138F; II in Fig. 1). Paldimycin trisodium has more favorable aqueous solubility and pharmacokinetic properties than the native paulomycin3. The mono-N-acetyl+cysteine adducts are also potential impurities in the paldimycin. The structures of paulomycin and paldimycin trisodium are shown in Fig. 1. There are two molecular forms of each compound, designated A and B, differing by a