Effects of type of vehicles on the dissolution rate of a poorly soluble drug : nitrofurantoin

Abstract EN

The dissolution rate of nitrofurantoin from different aqueous and oily suspensions containing different pharmaceutical excipients was investigated.

Flask-stirrer method was used.

The exposure of nitrofurantoin solutions (standard solutions and the solution in the dissolution flask, to light was minimized as far as possible.

The time required for 50% of the drug to appear in solution, i.e t50% , calculated from individual dissolution rate curves for each formulation, was used as an index of the dissolution rate of nitrofurantoin.

The results showed that significantly rapid release of nitrofurantoin (P<0.01) from aqueous vehicles compared with different oily vehicles (formulations).

A complex pattern of release of nitrofurantoin was shown from the different oily formulations depending partly on the viscosity of the vehicle and/or partly on the presence of sucrose or Cab-o-sil.

Possible reasons for these differences are discussed with particular reference to the Cab-o-sil or globules forming tendencies of sucrose containing oily formulations and the life times of these globules.