title: Identification and quantitation of polymyxin B, framycetin, and dexamethasone in an ointment by using thin-layer chromatography with densitometry.
abstract: A new thin-layer chromatographic-densitometric method has been developed for rapid identification and quantitative determination of polymyxin B, framycetin, and dexamethasone in a dental ointment. Silica gel 60 and F254 silica gel 60 plates were used for separating antibiotics and dexamethasone acetate, respectively. When determining framycetin and polymyxin B, chromatograms were developed by using 2 mobile phases, namely methanol and methanol-n-butanol-ammonia (25%)-chloroform (14 + 4 + 9 + 12, v/v/v/v/). The densitometric measurements were made at 550 nm after detection with 0.3% ninhydrin solution. Dexamethasone was determined by using the mobile phase cyclohexane-ethyl acetate (2 + 3, v/v) and ultraviolet densitometric recording at 245 nm. The results obtained for individual constituents with the chromatographic-densitometric method demonstrate similar accuracy, relative standard deviation values from 1.49 to 2.47%, and relative error values from 0.02 to 0.81% and are comparable to those obtained with the reference methods.
authors.affiliation: Jagiellonian University, Collegium Medicum, Department of Inorganic and Analytical Chemistry, 9 Medyczna St, 30-688 Cracow, Poland. jankrzek@cm-uj.krakow.pl
authors.forename: Jan
authors.initials: J
authors.lastname: Krzek
authors.forename: Anna
authors.initials: A
authors.lastname: Maślanka
authors.forename: Pawel
authors.initials: P
authors.lastname: Lipner
mesh_terms: D002855:Chromatography, Thin Layer / Q000379:methods*; D003720:Densitometry / Q000379:methods*; D003907:Dexamethasone / Q000032:analysis*; D005601:Framycetin / Q000032:analysis*; D009824:Ointments / Q000032:analysis* / Q000737:chemistry; D011112:Polymyxin B / Q000032:analysis*; D015203:Reproducibility of Results
chemical_list: D009824:Ointments; D005601:Framycetin; D003907:Dexamethasone; D011112:Polymyxin B