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

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 prop-erties for drug administration. This research was carried out to work on the pH dependent solubility im-provement 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 dis-played 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.