title: A novel electrostatic dry coating process for enteric coating of tablets with Eudragit® L 100-55.
abstract: An electrostatic dry coating process based on a liquid pan coater was developed for enteric coating of tablets with Eudragit® L 100-55. Two different liquid plasticizers of triethyl citrate (TEC) and PEG400 were used in the coating process. In contrast to TEC, PEG400 produced good powder adhesion and successful coating. DSC results showed that PEG400 lowered the glass transition temperature (Tg) of Eudragit® L 100-55 to a greater extent than TEC at the same blend ratio, indicating that PEG400 was more effective in plasticizing the polymer. PEG400 showed higher contact angle on both surfaces of tablet cores and coating powders as well as lower absorption into the tablet cores than TEC, suggesting that more PEG400 existed at the interface between tablet core and coating powders. The combination effects of higher plasticizing efficiency and more PEG400 available at the tablet surface produced higher plasticization of Eudragit® L 100-55, leading to the successfully initial powder adhesion. The powder adhesion was further enhanced by the electrostatically assisted coating process, as confirmed by the higher coating level and coating efficiency with electrical charging (60 kV) than the ones without it (0 kV). The micrographs of scanning electron microscopy and in vitro drug release tests of the coated tablets showed that higher curing temperature and longer curing time led to enhanced film formation and acid resistance. The electrostatic dry coating process has been demonstrated to be a promising process for enteric coating of tablets.
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Western Ontario, Ontario, Canada; Department of Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, China.
authors.forename: Mingxi
authors.initials: M
authors.lastname: Qiao
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Western Ontario, Ontario, Canada.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Western Ontario, Ontario, Canada.
authors.forename: Yingliang
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Western Ontario, Ontario, Canada. Electronic address: jzhu@uwo.ca.
authors.forename: Jesse
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Jiangsu Kanion Pharmaceut Co Ltd., Lianyungang, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D002951:Citrates / Q000737:chemistry; D004355:Drug Stability; D010968:Plasticizers / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011208:Powders / Q000737:chemistry; D012995:Solubility; D055672:Static Electricity; D013607:Tablets / Q000737:chemistry*; D044366:Transition Temperature
chemical_list: D002951:Citrates; D010968:Plasticizers; D011108:Polymers; D011109:Polymethacrylic Acids; D011208:Powders; D013607:Tablets; C038300:methylmethacrylate-methacrylic acid copolymer; D011092:Polyethylene Glycols; C023001:ethyl citrate