Synthesis of Cefixime–Gelatin Chemical Conjugated Microparticles and Their Antibacterial Activity Against Escherichia coli

Escherichia coli (E. coli) is a Gram-negative bacillus found in the intestine, which can also cause intestinal and extraintestinal illnesses in humans. Several hundred E. coli strains have been identified to cause diseases ranging from mild, self-limiting gastroenteritis to renal failure and septic shock. Its virulence allows E. coli to evade host defenses and develop resistance to common antibiotics. The aim of our study was to develop an aqueous-soluble cefixime conjugate for the treatment of E. coli infections. Cefixime shows excellent activity against E. coli strains. However, it has poor aqueous solubility. Thus, it was conjugated with gelatin using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) to produce a Cefixime–gelatin chemical conjugate (CGcc) with a significantly higher solubility than that of the pure drug, which may produce a better therapeutic effect. The conjugate was characterized using spectral data. The conjugate was determined to be non-hemolytic and non-toxic to L929 cells. The antibacterial activity of CGcc against E. coli was evaluated in vitro using the disc-diffusion method. The results showed that CGcc was slightly soluble in methanol, but very soluble in water and PBS, and its melting point was found to be 224–230 °C. The SEM images revealed that the CGcc exhibited a spherical morphology. All spectral data support the chemical conjugation of gelatin. The conjugation efficiency of CGcc was 74.54 ± 3.358%. In addition to its hemocompatibility and biocompatibility, CGcc exhibited enhanced solubility. The antibacterial effects revealed that CGcc exhibited good antibacterial activity against E. coli. CGcc showed a clear zone of inhibition and it was found to be 11.74 mm for 0.5 µg and 15.13 mm for 1 µg, respectively. Overall, the cefixime–gelatin chemical conjugate was effective in treating E. coli infections. This preliminary study may provide valuable insights into therapeutic effects during both preclinical and clinical trials. Detailed innovative methods are needed for the future alteration of gelatin and cefixime and integration of polymers into proper therapeutic applications.