Abstract: Two new groups of A-21978C cyclic peptides, anhydro- and isomer-A21978C peptide derivatives, have antibacterial activity and are useful as intermediates. The two groups are prepared via transpeptidation of the parent cyclic peptides. Pharmaceutical formulations containing the new peptides as active ingredients and methods of treating infections caused by susceptible Gram-positive bacteria with the formulations are also provided.The invention also provides an antibacterial composition containing the new drug substance LY 146032 in substantially pure form.

Abstract: An improved process for isolating A83543 factors from fermentation broth in which they are produced which comprises:a) adding an approximately equal volume of a water miscible, polar organic solvent to the fermentation broth, including the biomass thereof;b) separating the liquid phase of the resulting mixture from the biomass;c) adjusting the pH of the separated liquid phase to between about 7 and 13;d) applying the separated liquid phase directly to a column of nonfunctional, macroreticular polymer;e) eluting the A83543 components from the column with an aqueous solution of water miscible, polar organic solvent; andf) collecting the fractions containing A83543 components.

Abstract: This invention relates to a new chromatographic process for purifying fermentation products, particularly the antibiotic LY146032, from fermentation broths by use of a reverse phase non-functional resin.In the process of this invention the resin is loaded with the compound in the aqueous phase, the water then is removed from the resin and the resin converted to the organic phase for the resolution step. This process is applicable to purifying compounds which are adsorbed on reverse phase non-functional resins.

Abstract: Two new groups of A-21978C cyclic peptides, anhydro- and isomer-A21978C peptide derivatives, have antibacterial activity and are useful as intermediates. The two groups are prepared via transpeptidation of the parent cyclic peptides. Pharmaceutical formulations containing the new peptides as active ingredients and methods of treating infections caused by susceptible Gram-positive bacteria with the formulations are also provided. The invention also provides an antibacterial composition containing the new drug substance LY 146032 in substantially pure form.