Ampicillin Sodium

Ampicillin, which belongs to the aminopenicillins subgroup of β-lactams, is a broad-spectrum antibiotic that exerts bactericidal effect on both Gram-positive and Gram-negative bacteria. Due to its structural similarity to the D-Ala-D-Ala dipeptide, ampicillin forms a covalent bond by performing a nucleophilic attack on the serine residue in the active site of penicillin-binding proteins, which are involved in the synthesis of peptidoglycan, a fundamental component of the bacterial cell wall. As a result of ampicillin binding to PBP, PBP is inactivated and transpeptidation does not occur. Maintaining cell wall integrity is vital for the bacterium; however, when the PBP cannot perform its function, the necessary cross-links do not form, weakening the cell wall. A weakened cell wall becomes susceptible to osmotic stress, ultimately resulting in cell autolysis.
Ampicillin resistance can arise through various pathways, including β-lactamase production, changes in penicillin-binding proteins, loss of porin channels, and increased efflux pumps.

Fig. 1 Enzymatic hydrolysis of ampicillin via the β-lactamase. (Türkyılmaz O, Darcan C. 2006)

Sodium ampicillin was loaded into biocompatible hydrogels fabricated from chitosan and polyvinyl alcohol with cinnamon extract, using 3-aminopropyl(diethoxy)methylsilane as crosslinker for controlled drug delivery. The optimized hydrogel formulation released ampicillin sodium in a regulated manner in phosphate-buffered saline at pH 7.4, reaching up to 98.236 percent release over 90 minutes. The hydrogels exhibited pH-sensitive swelling behavior with maximum swelling at acidic pH and minimum at neutral and basic pH. SEM, FTIR and TGA characterization confirmed successful hydrogel formation and drug incorporation. These hydrogels represent a promising injectable controlled drug delivery system for ampicillin sodium.

Fig. 2 Preparation and characterization of ampicillin sodium-loaded biocompatible hydrogels. (Andlib H.; et al. 2024)