Novel pH-Responsive Carboxymethyl Cellulose/Pyrazolone Derivative/Fe3O4 Microbeads for Cephalexin Delivery

Abstract A novel magnetic nanocomposite scaffold (MPyC) was developed by synthesizing a new pyrazolone derivative of 4-(2-(4-bromophenyl)hydrazineylidene)− 5-methyl-2,4-dihydro-3 H -pyrazol-3-one (D3) conjugated with carboxymethyl cellulose (CMC). To enhance the structural functionality and integrity of the scaffold, ex-situ magnetite nanoparticles (Fe 3 O 4 ) were encapsulated within the CMC /D3 (PyC) composite. Cephalexin drug (CPX) was encapsulated within the polymeric PyC and MPyC carriers, which then fabricated in the form of beads by ionic gelation, followed by chemically stabilized using the crosslinking agent glutaraldehyde (GA). A comprehensive morphological and chemical characterization were applied to the prepared beads for in vitro pH-sensitive drug release approach. The MPyC scaffold showed a promising release efficiency of CPX by 99.35±4.9% at pH 1.7. A near-perfect fit related the Hixson-Crowell model was demonstrated in the release kinetic modelling data ( R 2 ≥ 0.99), suggesting that the rate of release is controlled by the declining surface area and uniform erosion of the MPyC beads. Also, the Korsmeyer-Peppas release exponent ( n = 0.7) verified an anomalous (non-Fickian) transport mechanism, in which drug release is driven by the coordinated effects of molecular diffusion and polymer matrix relaxation. Hence, the system introduced a dual-charged pH-sensitive nanocarriers, which exhibited its potential as a smart vehicle for controlled delivery of cephalexin.