title: Lipid-polymer composite microspheres for colon-specific drug delivery prepared using an ultrasonic spray freeze-drying technique.
abstract: Lipid-polymer composite microspheres (LP-MS) for colon-specific drug delivery were prepared using an ultrasonic spray freeze-drying technique. These microspheres, which consist of the pH-sensitive polymer Eudragit S100 and the non-polar lipid Compritol 888 ATO, were characterized by morphological and physicochemical properties. It was found that the LP-MS have a spherical lipid porous matrix with a smooth pH-sensitive polymer film on both internal and external surfaces, and the insoluble drug 10-hydroxycamptothecin was dispersed in an amorphous state in the carrier. Morphological changes of microparticles under different pH conditions were observed by confocal laser scanning microscopy, which showed that the lipid matrix in LP-MS restricted the swelling property of the polymer at pH 6.8. In drug release studies, less than 15% of the drug was released below pH 6.8, whereas more than 30% was released with a sustained-release model at pH 7.4. The LP-MS could provide a promising vehicle for colon drug delivery.
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Gao
authors.forename: Chun-Liu
authors.initials: CL
authors.lastname: Zhu
authors.forename: Xin-Xin
authors.initials: XX
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Gan
authors.forename: Yong
authors.initials: Y
authors.lastname: Gan
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage*; D002166:Camptothecin / Q000008:administration & dosage / Q000031:analogs & derivatives*; D003106:Colon / Q000378:metabolism*; D016503:Drug Delivery Systems; D005079:Excipients / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry*; D005612:Freeze Drying / Q000379:methods*; D006801:Humans; D008863:Microspheres; D009369:Neoplasms / Q000188:drug therapy; D010316:Particle Size; D011109:Polymethacrylic Acids / Q000737:chemistry*; D012995:Solubility; D014465:Ultrasonics / Q000379:methods
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D005079:Excipients; D005227:Fatty Acids; D011109:Polymethacrylic Acids; C086409:glyceryl behenate; C038300:methylmethacrylate-methacrylic acid copolymer; C028098:10-hydroxycamptothecin; D002166:Camptothecin