title: Development and validation of a stability-indicating high performance liquid chromatographic assay for benoxinate.
abstract: Benoxinate is a local anaesthetic used for ophthalmic applications. The aim of this study was to develop a rapid and simple stability-indicating method for the determination of benoxinate formulated for ophthalmic use, evaluate its long-term stability and identify its major degradation product. Benoxinate was eluted on a 10 microm Spherisorb phenyl column, 250 x 3.2 mm, with a mobile phase consisting of acetonitrile-buffer (pH 3.5) (35:65, v/v), pumped at 0.8 ml min(-1) flow rate. The buffer was composed of sodium dihydrogen phosphate (50 mM), sodium hydrogen sulfate (2.5 mM) and 1-heptanesulfonic acid sodium salt (5 mM). The analyte was quantified spectrophotometrically at 308 nm. The chromatograms of benoxinate formulations obtained by this method showed benoxinate (t = 4.5 min) well resolved from its degradation product (t = 2.3 min), which was separately identified by means of HPLC-MS as 4-amino-3-butoxybenzoic acid. The assay was demonstrated to have high accuracy, precision and linearity. The method was implemented in investigating the long-term stability of benoxinate 0.4% ophthalmic solutions. The method was found to be simple, quick and selective in determining benoxinate concentrations in fresh and aged preparations.
authors.affiliation: Research & Quality Control Laboratory, The Medical Corps, Mil. P.O. Box 02149, Israel Defense Force, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Chorny
authors.forename: Daniel
authors.initials: D
authors.lastname: Levy
authors.forename: Ilana
authors.initials: I
authors.lastname: Schumacher
authors.forename: Chaim
authors.initials: C
authors.lastname: Lichaa
authors.forename: Boris
authors.initials: B
authors.lastname: Gruzman
authors.forename: Oleg
authors.initials: O
authors.lastname: Livshits
authors.forename: Yossi
authors.initials: Y
authors.lastname: Lomnicky
mesh_terms: D000779:Anesthetics, Local / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D004356:Drug Storage; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D009883:Ophthalmic Solutions; D011343:Procaine / Q000031:analogs & derivatives* / Q000032:analysis*; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D000779:Anesthetics, Local; D007202:Indicators and Reagents; D009883:Ophthalmic Solutions; D011343:Procaine; C005298:benoxinate