title: Comparison of the Analgesic Effect of Diclofenac Sodium-Eudragit(®) RS100 Solid Dispersion and Nanoparticles Using Formalin Test in the Rats.
abstract: OBJECTIVE
  In this study the intensity and duration of analgesic effect of diclofenac Na - Eudragit(®) RS100 solid dispersion and nanoparticles were evaluated by using formalin test in the rats.
  
  
  METHODS
  The animals received different formulations of diclofenac Na and subsequently 50 μl of formalin solution (2.5%) was injected subcutaneously in the right paws after 1 h, 2 h and 3 h. The paw licking behavior was then evaluated in two phases. A dose of 20 mg/kg of pure diclofenac Na powder was determined as effective dose.
  
  
  RESULTS
  In the first phase, in term of reduced paw licking time, no significant differences were found in any of the groups compared to the control group. However, in the second phase, the animals which received pure drug powder and the physical mixture of diclofenac Na with Eudragit(®) RS100 showed significant differences at the first and second hours. In the animals received the nanoparticles and solid dispersion, significant differences were observed in the third hour compared to the control group.
  
  
  CONCLUSIONS
  The analgesic effect of diclofenac Na could be improved by formulating its nanoparticles and solid dispersion with Eudragit(®) RS100. However, the nanoparticles revealed significantly higher analgesic effect than solid dispersion.
authors: Drug Applied Research Center and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Khosro
authors: K
authors: Adibkia
authors: Clinical Psychiatry Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Alireza
authors: A
authors: Mohajjel Nayebi
authors: Drug Applied Research Center and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Mohammad
authors: M
authors: Barzegar-Jalali
authors: Students' Research Committee and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Siavash
authors: S
authors: Hosseinzadeh
authors: Students' Research Committee and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Saeed
authors: S
authors: Ghanbarzadeh
authors: Drug Applied Research Center and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Afshin
authors: A
authors: Shiva
keywords: Diclofenac sodium; Eudragit® RS100; Formalin test; Nanoparticles; Solid dispersion