STUDY OF PHYSICOCHEMICAL PARAMETERS AFFECTING THE RELEASE OF DICLOFENAC SODIUM FROM LIPOPHILIC MATRIX TABLETS

Maja Kincl,^a* Marija Meleh,^b Marjan Veber,^c and Franc Vrečer^d
a Physicochemical Development Department, R & D, Krka, d.d., Novo mesto,  Slovenia
^b Mass Spectrometry Department, R & D, Krka, d.d., Novo mesto, Slovenia 
^c University of Ljubljana , Faculty of Chemistry and Chemical Technology,  Ljubljana, Slovenia
^d New Formulations Research Department, R & D, Krka, d.d., Novo mesto,  Slovenia
* maja.kincl@krka.biz; tel.: +38673313824

  Abstract

In the present work different parameters, which influence the release of diclofenac sodium (2-[(2,6-dichlorophenyl)amino]benzeneacetic acid mono sodium salt) from lipophilic matrix prolonged release tablets, were investigated.

Solubility characteristics of diclofenac sodium in aqueous media with various ionic strengths, ionic compositions and pH in the range of 1 to 10 were determined. According to the obtained results different experimental conditions of the dissolution test on the drug release profiles were studied, i.e. different dissolution apparatus, various rotation speeds of the stirring elements, different buffer media with a pH in the range of 5.8 to 10.0 and various ionic strengths. The amount of released diclofenac sodium was determined by ultraviolet spectrophotometry at the wavelength of maximum absorbance at 276 ± 2 nm.

From the obtained results it can be concluded, that solubility of diclofenac sodium depends mainly on composition and pH of the dissolution medium and also on ionic strengths of the dissolution medium. Besides these parameters, on the release of diclofenac sodium from lipophilic matrix tablets influence also type of dissolution apparatus and particularly rotation speeds of the stirring elements.

Key words: drug release, lipophilic matrix tablets, ionic strengths, diclofenac sodium