title: Stress degradation studies and kinetic determinations of duloxetine enteric-coated pellets by HPLC.
abstract: A stability-indicating HPLC assay method was developed for the quantitative determination of duloxetine (DLX) in a pharmaceutical dosage form in the presence of its degradation products, and kinetic determinations were evaluated in acid conditions and UV-C radiation exposure. Chromatographic separation was achieved by use of an ACE C18 column (250 x 4.0 mm id, 5 microm particle size). The mobile phase was prepared by mixing aqueous 50 mM potassium phosphate buffer (pH 6.0 containing 0.3% triethylamine) and acetonitrile (60 + 40, v/v). DLX was rapidly degraded in an acid medium and in the presence of hydrogen peroxide and UV-C radiation; it was more stable in alkaline medium. The described method was linear over a range of 4.0-14.0 microg/mL for determination of DLX (r = 0.9998). The precision was demonstrated by the RSD of intraday (0.79-1.07%) and interday (0.85%) studies. The mean recovery was found to be 100.56%. The acid degradation of DLX in 0.1 M HCI solution showed an apparent zero-order kinetics (k = 0.177 microg/mL/min), and the photodegradation demonstrated an apparent first-order kinetics (k = 0.082 microg/mL/min). The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of DLX in enteric-coated pellets.
authors.affiliation: Universidade Federal do Rio Grande do Sul (UFRGS), Faculdade de Farmácia, Programa de Pós-Graduação em Ciências Farmacêuticas, Porto Alegre, RS, Brazil. patriciagomes0@yahoo.com.br
authors.forename: Patrícia
authors.initials: P
authors.lastname: Gomes
authors.forename: Nathalie R
authors.initials: NR
authors.lastname: Wingert
authors.forename: Clésio S
authors.initials: CS
authors.lastname: Paim
authors.forename: Elfrides E S
authors.initials: EE
authors.lastname: Schapoval
authors.forename: Martin
authors.initials: M
authors.lastname: Steppe
mesh_terms: D000928:Antidepressive Agents / Q000032:analysis* / Q000528:radiation effects; D002214:Capsules; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D000068736:Duloxetine Hydrochloride; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007700:Kinetics; D008027:Light; D010777:Photochemistry; D012015:Reference Standards; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D013608:Tablets, Enteric-Coated; D013876:Thiophenes / Q000032:analysis* / Q000528:radiation effects
chemical_list: D000928:Antidepressive Agents; D002214:Capsules; D007202:Indicators and Reagents; D013608:Tablets, Enteric-Coated; D013876:Thiophenes; D000068736:Duloxetine Hydrochloride