title: Stability of phenoxybenzamine hydrochloride in various vehicles.
abstract: The stability of phenoxybenzamine hydrochloride in various oral liquids was studied. Phenoxybenzamine hydrochloride powder or capsules were combined with various vehicles to prepare 10-mL formulations with a drug concentration of 2 mg/mL and a 20-mL stock solution containing 10 mg/mL. All formulations were prepared in triplicate and stored at 4 degrees C. A 1.0-mL sample of each of the 2-mg/mL formulations was withdrawn on days 0, 1, 2, 3, and 4, and samples of selected formulations were taken on days 7 and 10. Samples of the stock solution were withdrawn on days 0, 2, 4, 7, 10, 14, and 30. All samples were analyzed by high-performance liquid chromatography. Phenoxybenzamine hydrochloride 2 mg/mL was stable for a longer time in 1% propylene glycol, 0.15% citric acid, and water than in a similar vehicle in which syrup was used in place of water. The concentrations of the drug in both the 10-mg/mL stock solution and stock solutions diluted to 2 mg/mL were > 90% of the initial drug concentration for 30 days. Phenoxybenzamine hydrochloride 2 mg/mL in 1% propylene glycol and 0.15% citric acid in distilled water was stable for 7 days at 4 degrees C. A stock solution of phenoxybenzamine hydrochloride 10 mg/mL in propylene glycol was stable for 30 days at 4 degrees C and, after dilution with 66.7% sucrose in distilled water to a concentration of 2 mg/mL, for up to one hour at 4 degrees C.
authors.affiliation: Department of Pharmacy, National University of Singapore, Singapore.
authors.forename: L Y
authors.initials: LY
authors.lastname: Lim
authors.forename: L L
authors.initials: LL
authors.lastname: Tan
authors.forename: E W
authors.initials: EW
authors.lastname: Chan
authors.forename: K L
authors.initials: KL
authors.lastname: Yow
authors.forename: S Y
authors.initials: SY
authors.lastname: Chan
authors.forename: P C
authors.initials: PC
authors.lastname: Ho
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004339:Drug Compounding; D004355:Drug Stability; D014677:Pharmaceutical Vehicles; D010643:Phenoxybenzamine / Q000008:administration & dosage / Q000032:analysis*; D013997:Time Factors
chemical_list: D014677:Pharmaceutical Vehicles; D010643:Phenoxybenzamine