title: Quaternary polymethacrylate-magnesium aluminum silicate films: Water uptake kinetics and film permeability.
abstract: The aim of this study was to investigate the impact of the addition of different amounts of magnesium aluminum silicate (MAS) to polymeric films based on quaternary polymethacrylates (QPMs, here Eudragit RS and RL). MAS contains negatively charged SiO(-) groups, while QPM contains positively charged quaternary ammonium groups. The basic idea is to be able to provide desired water and drug permeability by simply varying the amount of added MAS. Thin, free films of varying composition were prepared by casting and exposed to 0.1M HCl and pH 6.8 phosphate buffer. The water uptake kinetics and water vapor permeability of the systems were determined gravimetrically. The transport of propranolol HCl, acetaminophen, methyl-, ethyl- and propylparaben across thin films was studied using side-by-side diffusion cells. A numerical solution of Fick's second law of diffusion was applied to determine the apparent compound diffusion coefficients, partition coefficients between the bulk fluids and the films as well as the apparent film permeability for these compounds. The addition of MAS resulted in denser inner film structures, at least partially due to ionic interactions between the positively charged quaternary ammonium groups and the negatively charged SiO(-) groups. This resulted in lower water uptake, reduced water vapor permeability and decreasing apparent compound diffusivities. In contrast, the affinity of the investigated drugs and parabens to the films substantially increased upon MAS addition. The obtained new knowledge can be helpful for the development of novel coating materials (based on QPM-MAS blends) for controlled-release dosage forms.
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Thitiphorn
authors.initials: T
authors.lastname: Rongthong
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand.
authors.forename: Srisagul
authors.initials: S
authors.lastname: Sungthongjeen
authors.affiliation: University of Lille, College of Pharmacy, 3 rue du Professeur Laguesse, 59006 Lille, France; INSERM U1008, Controlled Drug Delivery Systems and Biomaterials, 3 rue du Professeur Laguesse, 59006 Lille, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Siepmann
authors.affiliation: University of Lille, College of Pharmacy, 3 rue du Professeur Laguesse, 59006 Lille, France; INSERM U1008, Controlled Drug Delivery Systems and Biomaterials, 3 rue du Professeur Laguesse, 59006 Lille, France. Electronic address: juergen.siepmann@univ-lille2.fr.
authors.forename: Juergen
authors.initials: J
authors.lastname: Siepmann
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: thaned@kku.ac.th.
authors.forename: Thaned
authors.initials: T
authors.lastname: Pongjanyakul
mesh_terms: D000082:Acetaminophen / Q000737:chemistry; D000180:Acrylic Resins / Q000737:chemistry; D017607:Aluminum Compounds / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry; D004058:Diffusion; D005079:Excipients / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017616:Magnesium Compounds / Q000737:chemistry*; D010226:Parabens / Q000737:chemistry; D010539:Permeability; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry*; D011433:Propranolol / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D012995:Solubility; D012996:Solutions / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; D017607:Aluminum Compounds; D000538:Aluminum Silicates; D003692:Delayed-Action Preparations; D005079:Excipients; D017616:Magnesium Compounds; D010226:Parabens; D011108:Polymers; D011109:Polymethacrylic Acids; D000644:Quaternary Ammonium Compounds; D017640:Silicates; D012996:Solutions; D014867:Water; C030613:polymethacrylic acid; C050528:Eudragit RS; D000082:Acetaminophen; C033065:aluminum magnesium silicate; D011433:Propranolol; C006068:propylparaben
keywords: Diffusion coefficient; Eudragit RS/RL; Film permeability; Magnesium aluminum silicate; Quaternary polymethacrylate; Water uptake