Title: Piroxicam microemulsion: a promising carrier to reduce gastric irritation
Summary
Piroxicam is a non-steroidal anti-inflammatory drug belongs to BCS class II drugs having poor
solubility and is associated with a number of undesirable side effects on the stomach and kidneys
in addition to gastric mucosal damage. The aim was to investigate the phase behavior of systems
composed of pharmaceutically acceptable components; to prepare and characterize microemulsion
(ME) of piroxicam and determine its ex-vivo release and to evaluate in-vivo gastric irritation
caused by the pure piroxicam and compared with the piroxicam loaded microemulsion
formulation. Solubility studies were performed on different microemulsion components (oil,
surfactant and co-surfactant). Pseudo-ternary phase diagrams was constructed using water titration
method. Drug loaded microemulsion formulations were characterized for physical examination,
pH, viscosity, electrical conductivity, particle size, zeta potential, ex-vitro release study, stability
study and in-vivo gastric irritation study. Clove oil as oil, tween 20 as surfactant and polyethylene
glycol 400 (PEG 400) as co-surfactant, were selected on the basis of solubility. Surfactant mixture
1:1 ratio was selected based on the solubility results. ME region was identified from the phase
diagram and five formulations were selected. The prepared formulations were O/W. The results
indicated that as the water content increased in the MEs, ex-vivo release and conductivity of
formulations increased, while viscosity was decreased. Based on the particle size and cumulative
intestinal release, F3 formulation was selected for gastroprotective study. In vivo gastroprotective
study showed that piroxicam loaded ME formulation showed a profound decrease in gastric
irritation as compared to the reference product (pure piroxicam loaded). The study concluded that
ME is a promising carrier system for oral delivery of piroxicam with profound gastroprotective
activity