Study On Pharmacodynamics Of Ampicillin Sodium And Probenecid Sodium For Injection In Vivo

Initially antibiotics are product of metabolism of microorganisms which are able to inhibit or kill other microorganisms. Since 1940 penicillin was applied to clinic, many important antibiotics, such as streptomycin, chloromycetin, tetracycline and so on, emergence one after the other. In 1960's antibiotics walked into an age of semisynthesis after artificial semisynthetic penicillin was successfully synthetized. Ampicillin is a kind of semisynthetic penicillin, hydrogen of benzyl group in side chain R1 of penicillin replaced by amino group, which made it easy for ampicillin to permeate the coat of lipopolysaccharide and phospholipid of bacterial cell wall and destroy the synthesis of peptidoglycan. Therefore, ampicillin is a broad-spectrum antibiotic which has a strong antibacterial action against Gram-negative bacteria. When the carboxyl group of ampicillin was combined with sodium, ampicillin became ampicillin sodium, a dissolvable substance proper for intramuscular or intravenous injection. The antibacterial activity of ampicillin is similar to that of Penicillin G against Gram-positive bacteria, superior to it against Streptococcus riridans and enterococci, but inferior to it against other bacteria, and ineffective against penicillin G-resistant Staphylococcus aureus. Some Gram-negative bacteria, such as gonococci, meningococcus, Hemophilus influenzae, Bacillus pertussis, Escherichia coli, Bacillus paratyphosus, Bacillus typhi, Bacillus dysenteriae, Proteus mirabilis, Bacterium burgeri and so on, are sensitive to ampicillin but easily develop drug resistance. Ampicillin mainly cures various organ infections caused by sensitive bacteria, including urinary system, respiratory apparatus, biliary tract, intestinal tract, meningitis, encarditis and et al. Animal experiments and human body researches have established that the most important parameter determining in vivo antibacterial activity of beta-lactams is duration of serum free drug concentration above MIC of the specific pathogen. We called this phenomenon time-dependence killing mechanism. A T>MIC of 40-50% of the...