title: A simple and rapid high-performance liquid chromatographic method for determining tobramycin in pharmaceutical formulations by direct UV detection.
abstract: BACKGROUND
  Tobramycin, an aminoglycoside antibiotic, is a polar pharmaceutical compound which lacks a UV absorbing chromophore. Due to the absence of a UV absorbing chromophore and high polar nature of this antibiotic, the analysis of such compounds becomes a major challenge.
  
  
  OBJECTIVE
  To overcome these problems, a novel method for the determination aminoglycoside tobramycin was developed and validated based on reversed-phase high-performance liquid chromatography (RP-HPLC) with UV detector.
  
  
  METHODS
  An isocratic mobile phase consists of buffer 0.05 M diammonium hydrogen phosphate, pH adjusted to 10.0 using tetramethyl ammonium hydroxide. Chromatography was carried out at 25°C on a Purosphere RP-8e, 250 mm × 4.6 mm, 5mm. The detection was carried out using variable wavelength UV-Vis detector set at 210 nm. The compounds were eluted isocratically at a steady flow rate of 1.0 mL/min.
  
  
  CONCLUSIONS
  Tobramycin retention time was about 9.0 min with an asymmetry factor of 1.4. A logarithmic calibration curve was obtained from 0.47 to 0.71 mg/mL (r > 0.9998). Within-day %RSD was 0.29 (n = 6, 0.60 mg/mL) and between-day %RSD was 0.54 Specificity/ selectivity experiments revealed the absence of interference from excipients, recovery from spiked samples was between 99.0-100.0 percent.
  
  
  CONCLUSIONS
  A HPLC method based on UV detection has been developed and validated for determination of tobramycin from ophthalmic solution. The method is simple, rapid, specific, accurate (error 0.80%), precise (RSD <2.0%) and linear (r2=0.9998). The described method is suitable for routine analysis and quality control of ophthalmic solution containing tobramycin.
authors.affiliation: Department of Pharmaceutical Technology, Anna University of Technology, Thiruchirappalli, Trichy, Tamilnadu, India.
authors.forename: K
authors.initials: K
authors.lastname: Ruckmani
authors.forename: Saleem Z
authors.initials: SZ
authors.lastname: Shaikh
authors.forename: Pavne
authors.initials: P
authors.lastname: Khalil
authors.forename: M S
authors.initials: MS
authors.lastname: Muneera
keywords: Amino glycoside; derivatization; isocratic; reverse phase chromatography; tobramycin