Apalcillin is a naphthydridine derivative of ampicillin. Apalcillin has a broad spectrum of antibacterial activity that is very similar to that of piperacillin, except that apalcillin is significantly more active against Pseudomonas aeruginosa and Acinetobacter spp. Against Acinetobacter spp., apalcillin is uniquely active, compared to the other penicillins and comparison drugs. Strains producing high amounts of β-lactamases do become resistant to apalcillin. PAH (p-aminohippurate) clearance was significantly decreased during apalcillin infusion. Apalcillin appeared to compete with PAH for proximal tubular secretion but induced no further renal dysfunction.

Azithromycin is one of the world's best-selling antibiotics, used to treat or prevent certain bacterial infections: Acute bacterial exacerbations of chronic bronchitis in adults; acute bacterial sinusitis in adults; uncomplicated skin and skin structure infections in adults; urethritis and cervicitis in adults; genital ulcer disease in men; acute otitis media in pediatric patients; community-acquired pneumonia in adults and pediatric patients; pharyngitis/tonsillitis in adults and pediatric patients. Azithromycin should not be used in patients with pneumonia who are judged inappropriate for oral therapy because of moderate to severe illness or risk factors. A team of researchers at the Croatian pharmaceutical company Pliva, discovered azithromycin in 1980. It was patented in 1981. In 1986, Pliva and Pfizer signed a licensing agreement, which gave Pfizer exclusive rights for the sale of azithromycin in Western Europe and the United States. Pliva put its azithromycin on the market in Central and Eastern Europe under the brand name of Sumamed in 1988. Pfizer launched azithromycin under Pliva's license in other markets under the brand name Zithromax in 1991. Azithromycin is a semi-synthetic macrolide antibiotic of the azalide class. Like other macrolide antibiotics, azithromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit of the bacterial 70S ribosome. Binding inhibits peptidyl transferase activity and interferes with amino acid translocation during the process of translation. Its effects may be bacteriostatic or bactericidal depending of the organism and the drug concentration. Its long half-life, which enables once daily dosing and shorter administration durations, is a property distinct from other macrolides.