Preparation of pH-sensitive carboxymethyl cellulose/bovine serum protein complex particles and investigation of their drug carrying capacity

In this work, structurally stable and high-performance drug deliver composite particles were prepared successfully through a portable and simple electrostatic self-assembly method with carboxymethyl cellulose (CMC) and bovine serum protein (BSA). When regulating the pH value of the system lower than the isoelectric point of BSA, it exhibited positivity and was assembled with CMC through electrostatic attraction. The prepared composite particles were characterized, and different factors impacting on the composite materials were investigated. Amoxicillin and theophylline were selected as the experimental drugs to test the drug sustained-release performance of the composite particles. Results indicated that the composite particles possessed uniform shape, with an average particle size of 255 nm before heating and a PDI of 0.16 before heating. After heating, the particle size increased to 296 nm with PDI of 0.219. The encapsulation rate of amoxicillin and theophylline were found to be 44.1% and 58.9%, and the sustained-release curve demonstrated excellent drug loading efficiency and sustained release ability. This study demonstrates the potential application of CMC, a biocompatible natural high molecular weight material, in the delivery of small molecule drugs. It also demonstrates the development potential of composite systems composed of proteins such as BSA and polysaccharides.