[Preparation and property study of ion-exchange embolic microspheres for delivering pingyangmycin].
OBJECTIVE
To develop and study the properties of ion-exchange polyvinyl alcohol-acrylic acid microspheres (PVA-AA-Ms) for embolization.


METHODS
The PVA-AA-Ms were produced by the method of inverse suspension polymerization. The morphology and particle size were determined by optical microscope; FT-IR was used to investigate the special functional groups of PVA-AA-Ms; the carboxyl content of PVA-AA-Ms was measured by chemical titration; the compression elasticity was examined by texture analyzer (TA-plus). Pingyangmycin (bleomycin A(5)) was used as model drug to prepare drug-loaded PVA-AA-Ms. Drug loading and entrapment efficiency were measured through UV-spectrophotometer; in vitro drug release characteristic was detected by constant temperature vibration dialysis assay.


RESULTS
The PVA-AA-Ms were round and integrated. The average diameter of PVA-AA-Ms was 500 microm with a range of 150-1 000 microm. The carboxyl vibration was demonstrated by FT-IR and the content of carboxyl was 8.905 mmol/g. PVA-AA-Ms were mechanically stable with appropriate elasticity. Drug loading and entrapment efficiency were 30 g/L and 99.4%, respectively. The drug release rate was slow in phosphate buffer solution (PBS), 88.3% of the drug was released after 24 h and the t(50) was 2.19 h.


CONCLUSIONS
PVA-AA-Ms prepared in this study were supposed to be suitable for clinical embolization according to the physicochemical properties. The high carboxyl content of PVA-AA-Ms which allowed them to load cationic drugs (e.g., drug with amino group) through ion-exchange mechanism brought broad prospects for combination of embolization and chemotherapy.
Yuan
Hui-yan
HY
Department of Pharmaceutics, Peking University School of Pharmaceutical Sciences, Beijing 100191, China.
Zhang
Yuan
Y
Fan
Tian-yuan
TY
D000179:Acrylates / Q000737:chemistry*; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage*; D001761:Bleomycin / Q000008:administration & dosage / Q000031:analogs & derivatives*; D016461:Chemoembolization, Therapeutic; D004337:Drug Carriers / Q000737:chemistry*; D007474:Ion Exchange; D008863:Microspheres; D011142:Polyvinyl Alcohol / Q000737:chemistry*
D000179:Acrylates; D000903:Antibiotics, Antineoplastic; D004337:Drug Carriers; C106069:PVA-AA; D001761:Bleomycin; C025703:bleomycetin; D011142:Polyvinyl Alcohol