Electro-microgellation of CS/PL spheres self-embedded with in situ AgNPs formation as a losartan delivery system

Abstract Given rise to a green chemistry, in a single step, electro-microgelation of chitosan (CS)-pullulan (PL) hybrid system self-embedded with in situ formed silver nanoparticles (AgNPs) avoiding the presence of reducing and/or crosslinking agent was prepared and introduced as a drug carrier system of losartan as a model drug. The formation, morphology, size distribution, compositional and structural features of the microgel and AgNPs have been characterized by transmission electron microscopy (TEM), UV– visible measurements (UV–vis). The compositional and structural features of the microgels were revealed by Fourier transform infrared spectroscopy (FTIR), induced coupled plasma (ICP) and Zeta potential analysis. Losartan (LOS) entrapment within the microgel network possibility was examined using UV–Vis and TEM measurements. The results revealed that a uniform AgNPs with average narrow size distribution 5.4 nm and border to border interparticle distance 1.22 nm successfully self-embedded within in situ electrosynthesised chitosan-pullulan hybrid microgels of a dual size distribution (151.4 and 43.5 nm) with a positive surface charge +25 ± 5.18 mV guarantee the electrostatic repulsion between the particles. Besides, the incorporation of AgNPs during the electrosynthesis process played a crucial role in the morphology transition from pearl-necklace to microsphere structure. Furthermore, stability examination of the colloidal microgel particles introduced that the single particle contains Ag + ions undergo a slow reduction rate in consistency with a nucleation favored over growth. On the other hand, the obtained microgel particles have a good antibacterial activity against Gram-positive and Gram-negative bacteria. Investigation of the ability of the losartan incorporation inside the microgel particles during the microgel preparation explored that a stable core/shell like structure (core: losartan and shell: AgNPs@CS/PL) was effectively formed with average size 95 nm and zeta potential +39 mV promoting the particles stability.