title: Quantification of betamethasone in human plasma by liquid chromatography-tandem mass spectrometry using atmospheric pressure photoionization in negative mode.
abstract: Betamethasone is a synthetic corticosteroid designed to exert a marked glucocorticoid activity. As the free alcohol, betamethasone finds widespread clinical applications related to its anti-inflammatory and immunosuppressant activity. In the present study, a fast, sensitive, robust method was developed for the determination and quantification of betamethasone in human plasma by liquid chromatography coupled with tandem mass spectrometry, using photospray ionization in negative mode. Betamethasone was extracted from 0.5 ml human plasma by liquid-liquid extraction (LLE) using chloramphenicol as internal standard. The method has a chromatographic run of 2.5 min using a C(18) analytical column (100 mm x 2.1 mm i.d.) and the linear calibration curve over the range was linear from 0.05 to 50 ng ml(-1) (r(2)>0.993). The between-run precision, based on the relative standard deviation replicate quality controls was 94.1% (0.15 ng ml(-1)), 90.7% (4.0 ng ml(-1)) and 97.2% (40 ng ml(-1)). The between-run accuracy for the above-mentioned concentrations was 11.9, 9.0 and 9.8%, respectively. The method herein described was employed in a bioequivalence study of two formulations of dexchlorpheniramine/betamethasone 2 mg/0.25 mg tablets.
authors.affiliation: Galeno Research Unit, Latino Coelho St., 1301 Parque Taquaral, 13087-010 Campinas, SP, Brazil.
authors.forename: Alberto Dos Santos
authors.initials: Ados S
authors.lastname: Pereira
authors.forename: Lina S O B
authors.initials: LS
authors.lastname: Oliveira
authors.forename: Gustavo D
authors.initials: GD
authors.lastname: Mendes
authors.forename: Jorge J
authors.initials: JJ
authors.lastname: Gabbai
authors.forename: Gilberto
authors.initials: G
authors.lastname: De Nucci
mesh_terms: D001623:Betamethasone / Q000097:blood* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013810:Therapeutic Equivalency
chemical_list: D001623:Betamethasone