Preparation and characterization of Pingyangmycin-loaded bovine serum albumin microspheres for embolization therapy

Bovine serum albumin microspheres (BSA-MSs) containing Pingyangmycin hydrochloride (PYM) were prepared for the interventional embolization by an emulsification-crosslinking method. The average diameter of the MSs was 83.6 μm with 80% ranging from 35 to 200 μm. The MSs showed a rather high entrapment efficiency (EE%) of 87.6 ± 5.7% and the drug loading efficacy (DL%) was 20.2 ± 1.3%. The drug release behaviors were evaluated both in vitro and in vivo, using UV-spectroscopy and HPLC, respectively. The in vitro results showed a significantly delayed release of drug for 10 days. The central auricular artery of rabbit was chosen as an embolization sites to study the in vivo drug release and the pharmacokinetics of the MSs compared with PYM injections. Experiments performed by artery perfusion and embolization in rabbits central auricular artery revealed that the PYM loaded BSA-MSs (PYM-BSA-MSs) could obviously prolong in vivo drug release, extend the mean residence time (MRT) and had equal bioavailability compared with plain PYM injections. These results demonstrated that by embolization of the central auricular artery with PYM-BSA-MSs, the local drug concentration could maintain at a relative high level for a longer time, thus achieve the aim of tumor targeting therapy. PYM-BSA-MSs are excellent potential alternatives of interventional embolization materials for the treatment of maxillofacial region tumors.