title: Investigation of potential ionic interactions between anionic and cationic polymethacrylates of multiple coatings of novel colonic delivery system.
abstract: The objective of this work was to investigate potential interactions between anionic (Eudragit FS) and cationic (Eudragit RL) polymethacrylates of multiple coatings of a novel colonic drug delivery system. Aqueous films of pure polymers Eudragit FS (FS) and Eudragit RL (RL) and their superimposedfilm (FS-RL) were cast on glass slabs. The potential ionic interactions were studied by analysing the dried films using differential scanning calorimetry (DSC), Fourier transform-infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR). The glass transition temperatures (Tg) of pure RL and FS were 60 degrees C and 22 degrees C, respectively; FS-RL showed two distinct glass transitions at 59 degrees C and 24 degrees C in the second heating cycle. In the 13C-MAS spectra of the samples in the solid state, no shifts of the resonance could be detected in the superimposed film compared with the pure polymers. The FT-IR spectra of the superimposed film did not show any significant shift of the bands of the -NMe3+ group of RL and the -COO- function of FS compared with the spectra of the pure polymers. No ionic interactions between anionic and cationic polymethacrylates were revealed by DSC, FT-IR, and NMR.
authors.affiliation: University of Georgia, College of Pharmacy, Department of Pharmaceutical and Biomedical Sciences, Athens 30602, USA. vishal.k.gupta@pharmacia.com
authors.forename: Vishal K
authors.initials: VK
authors.lastname: Gupta
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Beckert
authors.forename: Norbert J
authors.initials: NJ
authors.lastname: Deusch
authors.forename: Madhusudan
authors.initials: M
authors.lastname: Hariharan
authors.forename: James C
authors.initials: JC
authors.lastname: Price
mesh_terms: D000838:Anions / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003106:Colon; D016503:Drug Delivery Systems; D011108:Polymers / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
chemical_list: D000838:Anions; D002412:Cations; D011108:Polymers; C058665:Eudragit RL; D019904:Polymethyl Methacrylate