Encapsulation of Piroxicam in Microemulsion to Avoid Gastric Irritation

Abstract

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. Each formulation was prepared in duplicate i.e. drug loaded. The study concluded
that ME is a promising carrier system for oral delivery of piroxicam with profound gastroprotective activity