This work was first development of a delivery system capable of maintaining a sustained release of protein drugs at specific sites by using potentially biocompatible porcine articular cartilage. The prepared porcine articular cartilage powder (PCP) was easily soluble in phosphate-buffered saline. The PCP suspension easily entrapped bovine serum albumin-fluorescein isothiocyanate (BSA-FITC) in pharmaceutical formulations at room temperature. The aggregation of PCP and BSA-FITC was confirmed by dynamic light scattering. When the BSA-FITC-loaded PCP suspension was subcutaneously injected into rats, it gelled and formed an interconnecting three-dimensional PCP structure that allowed BSA to penetrate through it. The amount of BSA-FITC released from the PCP hydrogel was determined in rat plasma and monitored by real-time in vivo molecular imaging. The data indicated sustained release of BSA-FITC for 20 days in vivo. In addition, the PCP hydrogel induced a slight inflammatory response. In conclusion, we showed that the PCP hydrogel could serve as a minimally invasive therapeutics depot.Graphical abstract
A BSA-loaded porcine articular cartilage powder (PCP) suspension at room temperature easily gelled upon s.c. injection into rats and exhibited sustained release of BSA over extended experimental periods.