title: Development and characterization of a gastroretentive dosage form composed of chitosan and hydroxyethyl cellulose for alendronate.
abstract: In this study, alendronate, the most commonly used biphosphonate for treating osteoporosis, was formulated as gastroretentive dosage form (GRDF) tablets to enhance its oral bioavailability. GRDF tablets were characterized with the effects of different molecular weights (MWs) of chitosan (CS) and hydroxyethyl cellulose (HEC) at various ratios on swelling, floating, and physical integrity. The CS component was formed using various acids: acetic, lactic, malic, succinic, and citric, and a high viscosity grade of HEC was selected. The results demonstrated that the swelling ratios of the formulations comprising high MW CS were lower than those of low or medium MW CS when salts were formed with any countering acids except for acetic acid. The decreasing ranking of the swelling rates was: CS-citrate > CS-malate > CS-lactate > CS-succinate > CS-acetate. A negative correlation was found between the pKa of the respective countering acid and the swelling rate. The swelling rate was promoted if an acidic salt of CS with a lower water content was incorporated, while it became slower when tablet hardness was higher or the compression force to form tablets was increased. Although HEC did not contribute to swelling or floating, it played a role in maintaining structural integrity. A prolonged dissolution profile of alendronate GRDF tablets developed in this study was observed.
authors.affiliation: School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
authors.forename: Ying-Chen
authors.initials: YC
authors.lastname: Chen
authors.affiliation: School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
authors.forename: Hsiu-O
authors.initials: HO
authors.lastname: Ho
authors.affiliation: School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chiao-Chi
authors.initials: CC
authors.lastname: Chiu
authors.affiliation: School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan ; Clinical Research Center and Traditional Herbal Medicine Research Center, Taipei Medical University Hospital, Taipei, Taiwan.
authors.forename: Ming-Thau
authors.initials: MT
authors.lastname: Sheu
mesh_terms: D019386:Alendronate / Q000008:administration & dosage* / Q000737:chemistry; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D002482:Cellulose / Q000008:administration & dosage / Q000031:analogs & derivatives*; D048271:Chitosan / Q000008:administration & dosage*; D012995:Solubility; D013607:Tablets
chemical_list: D050071:Bone Density Conservation Agents; D013607:Tablets; D002482:Cellulose; C002283:hydroxyethylcellulose; D048271:Chitosan; D019386:Alendronate
keywords: alendronate; chitosan; gastroretentive dosage form; hydrogel; hydroxyethyl cellulose; swelling