title: Preparation and characterization of metoprolol controlled-release solid dispersions.
abstract: In recent years, great attention has been paid to using solid dispersions to make sustained-release drugs. The objective of this study is to produce sustained-release systems of metoprolol tartrate using solid dispersion techniques and to evaluate their physicochemical characteristics. The solid dispersions were produced by melting and solvent methods, containing 7%, 15%, or 25% of the drug and different ratios of Eudragit RLPO and RSPO in ratios of 0:10, 3:7, 5:5, 7:3, and 10:0. Drug release profiles were determined by USP XXIII rotating paddle method in phosphate buffer solution (pH 6.8). XRD, DSC, IR, and microscopic observations were performed to evaluate the physical characteristics of solid dispersions. Results showed that the drug release from dispersions was at a slower rate than pure drug and physical mixtures. Moreover, the formulations containing greater ratios of Eudragit RSPO showed slower release rates and smaller DE8% but larger mean dissolution time than those containing greater ratios of Eudragit RLPO. Dispersions with particle size of less than 100 microm containing 7% of metoprolol and Eudragit RL:RS 5:5 (solvent method) and those with the ratio of 3:7 (melting method) had similar release pattern to Lopressor sustained-release tablets by zero-order and Higuchi kinetics, respectively.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran. varshosaz@pharm.mui.ac.ir
authors.forename: Jaleh
authors.initials: J
authors.lastname: Varshosaz
authors.forename: Hossein
authors.initials: H
authors.lastname: Faghihian
authors.forename: Kobra
authors.initials: K
authors.lastname: Rastgoo
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000319:Adrenergic beta-Antagonists / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D008790:Metoprolol / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012995:Solubility
chemical_list: D000180:Acrylic Resins; D000319:Adrenergic beta-Antagonists; D003692:Delayed-Action Preparations; D011108:Polymers; C050528:Eudragit RS; C058665:Eudragit RL; D008790:Metoprolol