Caffeic Acid-PLGA Conjugate to Design Protein Drug Delivery Systems Stable to Irradiation

This work reports the feasibility of caffeic acid grafted PLGA (g-CA-PLGA) to design biodegradable sterile microspheres for the delivery of proteins. Ovalbumin (OVA) was selected as model compound because of its sensitiveness of \u3b3-radiation. The adopted grafting procedure allowed us to obtain a material with good free radical scavenging properties, without a significant modification of Mw and Tg of the starting PLGA (Mw PLGA = 26.3 \ub1 1.3 kDa vs. Mw g-CA-PLGA = 22.8 \ub1 0.7 kDa; Tg PLGA = 47.7 \ub1 0.8 \ub0C vs. Tg g-CA-PLGA = 47.4 \ub1 0.2 \ub0C). By using a W1/O/W2 technique, g-CA-PLGA improved the encapsulation efficiency (EE), suggesting that the presence of caffeic residues improved the compatibility between components (EEPLGA = 35.0% \ub1 0.7% vs. EEg-CA-PLGA = 95.6% \ub1 2.7%). Microspheres particle size distribution ranged from 15 to 50 \ub5m. The zeta-potential values of placebo and loaded microspheres were -25 mV and -15 mV, respectively. The irradiation of g-CA-PLGA at the dose of 25 kGy caused a less than 1% variation of Mw and the degradation patterns of the non-irradiated and irradiated microspheres were superimposable. The OVA content in g-CA-PLGA microspheres decreased to a lower extent with respect to PLGA microspheres. These results suggest that g-CA-PLGA is a promising biodegradable material to microencapsulate biological drugs

Preparation and characterization of caffeic acid grafted PLGA microspheres

Introduction Phenolic compounds are known to have antioxidant properties mainly because they can act as free-radical scavengers since the hydroxyl groups can donate an electron or hydrogen atom to a free radical. Recently, phenolic compounds grafted onto the backbone of poly(lactide-co-glycolide) (PLGA) were proposed as novel biodegradable materials stable to sterilization by gamma- irradiation at the dose of 25 kGy [1]. Nevertheless, no information on the feasibility to encapsulate biological drug products have been available