Design of pH-Responsive Solid Dispersion of Piroxicam for Increased Solubility and Lower Gastric Side Effects

Abstract

Piroxicam is one of the most potent non-steroidal anti-inflammatory drugs (NSAIDs), but is
notorious for gastric adverse events associated with its long-term use along with poor physicochemical properties for drug administration. This research was carried out to work on the pH dependent solubility improvement aspect of solid dispersion as a viable oral drug formulation to avoid the gastric side effects of drug
without the need of an extra step of application of a gastro-resistant coating in the making of the finished
drug product. Eudragit L100 (L100) was investigated as the pH responsive carrier and was compared for
dissolution enhancement with the established hydrophilic polymers. All the preparations were found to be
in amorphous form with reduced size of particles and enlarged surface area. L100 based formulations displayed comparable increase in solubility and dissolution in the intestinal medium (pH 6.8) as the commonly
used hydrophilic carriers, polyethylene glycol (PEG-6000) and polyvinylpyrrolidone (PVP-K30). However,
only L100 avoided drug leakage in the gastric medium (pH 1.2), less than 20 % for 2 h. It was found helpful
and reasonable method for achieving better solubility and dissolution of water insoluble drugs that pose
gastric side effects.