Vancomycin hydrochloride: Vancomycin is a glycopeptide antibiotic produced by the growth of Amycolatopsis orientalis (formerly Nocardia orientalis). It inhibits bacterial cell wall synthesis. Vancomycin prevents the synthesis of peptidoglycan by binding tightly to peptides containing D-alanyl-D-alanine at the free carboxyl end. Vancomycin has also been shown to alter the permeability of the cell membrane and may selectively inhibit RNA synthesis. Vancomycin is active against staphylococci, streptococci, enterococci, Clostridium difficile, and diphteroids. It is not active against gram-negative bacilli, mycobacteria or fungi. Vancomycin is poorly absorbed after oral administration; therefore, it is given intravenously. The mean elimination half-life of vancomycin from plasma is 4 to 6 hours in subjects with normal renal function. In the first 24 hours, about 75 % of the administered dose of vancomycin is excreted in urine by glomerular filtration.