title: Stability indicating HPLC method for the estimation of oxycodone and lidocaine in rectal gel.
abstract: An HPLC method for the quantification of oxycodone and lidocaine in a gel matrix is described. The mobile phase consisted of methanol--water--acetic acid (35:15:1 v/v/v) and was delivered at 1.5 ml/min through a 4.6 x 250 mm Zorbax SB-C8 column. Oxycodone was detected at 285 nm and lidocaine at 264 nm. Linear calibration curves were obtained for oxycodone in the range of 0.05--1.5% (w/w) and for lidocaine in the range of 0.1--5.0% (w/w). Oxycodone and lidocaine were treated with hydrogen peroxide and the oxidation products were readily separated on the column. The method was applied to assess the stability of a gel containing oxycodone hydrochloride (0.3% w/w) and lidocaine (1.5% w/w). The gel was stored under refrigeration in ready-to-use syringes and under these conditions oxycodone and lidocaine were stable for at least 1 year. The gel is useful in the management of tenesmus in rectal cancer.
authors.affiliation: Pharmacy Department, Repatriation General Hospital, Daw Park, Adelaide SA 5041, Australia. markus.gebauer@rgh.sa.gov.au
authors.forename: M G
authors.initials: MG
authors.lastname: Gebauer
authors.forename: A F
authors.initials: AF
authors.lastname: McClure
authors.forename: T L
authors.initials: TL
authors.lastname: Vlahakis
mesh_terms: D000285:Administration, Rectal; D000701:Analgesics, Opioid / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D005782:Gels; D008012:Lidocaine / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry*; D010098:Oxycodone / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry*
chemical_list: D000701:Analgesics, Opioid; D005782:Gels; D008012:Lidocaine; D010098:Oxycodone