Kinase experiment:

At 278 K, various concentrations of Penicillin G sodium salt, cefalexin and cefoxitin solutions are added to TEM-1β-lactamase solution (5×10-6 M). The concentrations of the three antibiotics are gradually increased from 0 to 25×10-6 M. Following mixing and interaction for 2 min, the Ultraviolet-visible (UV-Vis) absorption spectra are recorded on a spectrophotometer with a slit of 2 nm and scanning speed of 400 nm/min using 0.02 M phosphate buffer (pH 7.0) as a reference[1].

Animal experiment:

A randomized complete block design with 2 replicates is used for this study. Each replicate includes 448 pigs, with 16 pens and 28 pigs per pen. Pigs are also sorted by weight; such that animals of similar weight based on visual observation are grouped together within blocks. Two treatments are randomly assigned within each block of 2 contiguous pens using a formal randomization process. The treatment groups are Control (no treatment given) and Treated (Penicillin G sodium salt). Penicillin G sodium salt is administered via the drinking water for 5 d over 2 periods of treatment. The first treatment period commences on the day of weaning, when the pigs are moved into the nursery barns (Day 1) and ends on Day 5. The second treatment period begins on Day 21 and ends on Day 25. The Control group does not receive treatment[2].

IC50: 0.002 μg/ml for Streptococcus pneumoniae serotype 4

Penicillin G sodium is a penicillin antibiotic against sensitive organisms during the stage of active multiplication and acts by inhibiting the biosynthesis of bacterial cell wall mucopeptides. It is not active against penicillinase-producing bacteria, which include many strains of staphylococci.

In vitro: Penicillin G sodium works by interfering with the formation of the bacteria's cell wall. This weakens the cell wall and kills the bacteria. Penicillin G is highly effective in-vitro against staphylococci, streptococci and pneumococci. Other organisms sensitive in-vitro to penicillin G are Neisseria gonorrhoeae, Bacillus anthracis, Corynebacterium diphtheriae, Clostridia et al. Treponema pallidum is extremely sensitive [1].

In vivo: With intermittent intramuscular administration of penicillin normal rats were cured after doses of 4 mg/kg/d, whereas decomplemented rats recovered only after daily doses of above 100 mg/kg. When penicillin was administered by way of continuous infusion, doses of 3.5 mg/kg/d were required for a cure of infections in both normal and decomplemented rats [2].

Clinical trials: Penicillin G sodium is used to treat a wide variety of bacterial infections. It is also used to prevent the heart infection in patients with certain heart diseases who are having surgery. Penicillin G sodium is known as a natural penicillin antibiotic. It works by stopping the growth of bacteria [1].

Reference:
[1] Bakker-Woudenberg IA, van den Berg JC, Fontijne P, Michel MF.   Efficacy of continuous versus intermittent administration of penicillin G in Streptococcus pneumoniae pneumonia in normal and immunodeficient rats. Eur J Clin Microbiol. 1984 Apr;3(2):131-5.