Chitosan/Carboxymethyl Cellulose Nanocomposites Prepared via Electrolyte Gelation–Spray Drying for Controlled Ampicillin Delivery and Enhanced Antibacterial Activity

This study reports the fabrication of chitosan/carboxymethyl cellulose (C/M) nanocomposites by electrolyte gelation-spray drying and the evaluation of their antibacterial performance as carriers for the antibiotic ampicillin. Chitosan (C), a cationic biopolymer derived from chitin, was combined with the anionic polysaccharide carboxymethyl cellulose (M) at different mass ratios to form stable nanocomposites via electrostatic interactions and then collected by a spraying dryer. The resulting particles exhibited mean diameters ranging from 800 to 1500 nm and zeta potentials varying from +90 to −40 mV, depending on the C:M ratio. The optimal formulation (C:M = 2:1 ratio) achieved a high recovery yield (71.1%) and ampicillin encapsulation efficiency EE (82.4%). Fourier transform infrared spectroscopy (FTIR) confirmed the presence of hydrogen bonding and ionic interactions among C:M, and ampicillin within the nanocomposite matrix. The nano-microcomposites demonstrated controlled ampicillin release and pronounced antibacterial activity against Staphylococcus aureus, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.2 µg/mL and 5.3 µg/mL, respectively, which were lower than those of free ampicillin. These results indicate that the chitosan/carboxymethyl cellulose nano-microcomposites are promising, eco-friendly carriers for antibiotic delivery and antibacterial applications.