Background: Poor dissolution of Etodolac is one of the major challenges in achieving
the desired therapeutic effect in oral therapy.
Objective: This study aimed to assess the potential of the liquisolid compact technique in increasing
the rate of dissolution of Etodolac and thus its bioavailability.
Methods: Liquisolid compacts were prepared using PEG 400, Avicel PH-200 and Aerosil 200 as
non-volatile liquid, carrier and coating material, respectively. The optimisation was carried out by
applying a 32 full factorial design using Design expert software 188.8.131.52 to examine the effects of
independent variables (load factor and carrier: coating ratio) on dependent variables (angle of repose
and % cumulative drug release at 30 min [Q 30 min]). Assessment of bioavailability was based
on a pharmacokinetic study on rabbits and pharmacodynamics evaluation on rats, respectively.
Results: The formulation M3 was identified as the optimised formulation based on the better flow
(lower angle of repose) and a higher rate of dissolution (Q 30 min >95%). The higher dissolution rate
could be due to conversion of Etodolac into an amorphous molecularly dispersed state, availability
of larger surface area, enhancement of aqueous solubility and enhanced wetting of drug particles.
Studies with DSC, XRD, and SEM verified the transformation of Etodolac from crystalline to
amorphous state, a key factor responsible for improving the dissolution rate. The pharmacokinetic
profile of M3 was prominent, demonstrating higher absorption of Etodolac in comparison to oral
suspension and immediate-release conventional tablets in rabbits. Liquisolid formulation exhibited
a 27% increment in paw thickness as compared to 57% and 46% increments for oral suspension
and immediate-release conventional tablets, respectively, after 7 hrs in the carrageenan-induced
paw model in rats.
Conclusion: The results indicated the liquisolid compact technique to be a promising strategy to enhance
the bioavailability of Etodolac.