title: Stability studies on florfenicol using developed derivative spectrophotometric methods.
abstract: OBJECTIVE
  This study aims to investigate the stability of florfenicol using previously developed derivative spectrophotometric methods (D1and D2).
  
  
  METHODS
  The studied stability-indicating pararmeters included alkali (NaOH, 1M), acid (HCl, 1M), pH changes (buffer pH 2.2-11), temperature (80°C and 100°C at pH 10) and light.
  
  
  RESULTS
  A constructed pH profile for the drug degradation rate revealed a significant effect of pH on the drug stability between pH ranges 8 and 11. The obtained profile indicated first order dependence of Kobson [OH-]. Arrhenius plot at pH 10 was found linear at temperatures 80°C and 100°C with estimated activation energy of 19.35kcal/mol. The calculated rate constant (Kobs), t½and t90at 25°C were found to be 1.8×10-3h, 385h and 58.3h, respectively. The photostability of florfenicol was also studied by exposing the drug solution to direct sunlight during mid-day time.
  
  
  CONCLUSIONS
  The obtained results reflected the instability of florfenicol under the study conditions.
authors: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Khartoum, PO Box 1996, Khartoum, Sudan.
authors: M M
authors: MM
authors: Elimam
authors: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Khartoum, PO Box 1996, Khartoum, Sudan. Electronic address: sshantier@yahoo.com.
authors: S W
authors: SW
authors: Shantier
authors: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Khartoum, PO Box 1996, Khartoum, Sudan.
authors: E A
authors: EA
authors: Gadkariem
authors: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Khartoum, PO Box 1996, Khartoum, Sudan.
authors: M A
authors: MA
authors: Mohamed
authors: Department of Pharmaceutics, Faculty of Pharmacy, University of Khartoum, P.O. Box 1996, Khartoum, Sudan.
authors: Z
authors: Z
authors: Osman
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000528:radiation effects; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D019999:Pharmaceutical Solutions; D013056:Spectrophotometry, Ultraviolet; D013472:Sunlight; D013696:Temperature; D013839:Thiamphenicol / Q000031:analogs & derivatives* / Q000032:analysis / Q000528:radiation effects
chemical_list: D000900:Anti-Bacterial Agents; D019999:Pharmaceutical Solutions; C035534:florfenicol; D013839:Thiamphenicol
keywords: Derivative spectrophotometry; Dérivé spectrophotométrie; Florfenicol; Florfénicol; Stability studies; Études de stabilité