Ampicillin Trihydrate

Product Story

Ampicillin was first synthesized in 1961 at Beecham Research Laboratories in the UK by a team building on the 6-aminopenicillanic acid (6-APA) backbone technology that Beecham had pioneered in the late 1950s. It was the first semi-synthetic penicillin with clinically useful Gram-negative activity — a watershed moment in antibiotic history. By adding an amino group to the benzylpenicillin side chain, Beecham's chemists created a molecule that could penetrate the outer membrane of Gram-negative bacteria while retaining the potent anti-streptococcal activity of penicillin G. Launched as Penbritin in 1961, ampicillin opened the era of broad-spectrum penicillins and remained the world's most prescribed broad-spectrum penicillin until amoxicillin surpassed it in the 1980s.

Ampicillin exerts bactericidal activity by binding to penicillin-binding proteins (PBPs) and inhibiting the transpeptidation step of peptidoglycan synthesis in the bacterial cell wall, leading to osmotic lysis. The key structural feature distinguishing ampicillin from penicillin G is the alpha-amino group on the phenylacetyl side chain, which confers enhanced penetration through porin channels of Gram-negative outer membranes. This structural innovation extended the penicillin spectrum to include E. coli, Proteus mirabilis, Salmonella, Shigella, and H. influenzae, making it the first penicillin effective against common enteric and respiratory Gram-negative pathogens. Like all penicillins, ampicillin is susceptible to beta-lactamase hydrolysis, which led to the development of ampicillin-sulbactam combinations for beta-lactamase-producing strains.

Ampicillin's clinical niche endures in three areas where it remains irreplaceable: (1) neonatal sepsis and meningitis, where ampicillin + gentamicin is the standard empiric regimen worldwide; (2) IV therapy for serious infections including bacterial meningitis, endocarditis, and septicemia caused by susceptible organisms; and (3) cost-sensitive public health programs in low-resource settings, where ampicillin's lower API cost compared to amoxicillin makes it the preferred aminopenicillin. The trihydrate form is used for oral solid dosage forms, while ampicillin sodium is the injectable salt. The WHO lists ampicillin on its Model List of Essential Medicines.

As of mid-2026, global ampicillin API demand is estimated at 15,000-18,000 metric tons annually. While amoxicillin dominates the oral antibiotic market, ampicillin retains a strong position in injectable formulations and in veterinary medicine across Asia, Africa, and Latin America. China and India together account for approximately 80% of global ampicillin API production, with Chinese manufacturers controlling the upstream 6-APA and phenylglycine intermediate supply chains. KingWish supplies GMP-certified ampicillin trihydrate meeting USP/EP/CP standards, with full batch documentation and competitive lead times for pharmaceutical manufacturers worldwide.

Quality Specifications

Therapeutic Applications

• Respiratory tract infections: Oral and parenteral therapy for community-acquired pneumonia, acute exacerbations of chronic bronchitis, and sinusitis caused by susceptible organisms.
• Bacterial meningitis: High-dose IV ampicillin (in combination with third-generation cephalosporins) for empiric treatment of bacterial meningitis, particularly covering Listeria monocytogenes in neonates and the elderly.
• Neonatal sepsis: Ampicillin + gentamicin is the WHO-recommended first-line empiric regimen for neonatal sepsis, covering Group B Streptococcus and E. coli.
• Urinary tract infections: Effective for uncomplicated UTIs caused by susceptible Enterobacteriaceae; particularly useful in pregnancy where fluoroquinolones are contraindicated.
• Gastrointestinal infections: Oral ampicillin for shigellosis, salmonellosis (non-typhoidal), and typhoid fever where fluoroquinolone resistance is absent.