Enhancement in Dissolution Rate of Piroxicam by Two Micronization Techniques

Piroxicam is a nonsteroidal anti-inflammatory drug that is practically insoluble in water. The oral absorption rate of piroxicam is dependent on its dissolution rate in the GI tract. The aim of this study was to enhance the dissolution of piroxicam by a microcrystallization technique. The preparation of microcrystals of piroxicam was done by two methods, solvent change and pH shift. In the solvent-change method, the drug was dissolved in acetone, and the stabilizer was dissolved in water. The aqueous phase was added to acetone under homogenization in an ice bath for 1 min. In the pH-shift method, the drug and stabilizer were both dissolved in 0.1 N NaOH (pH 12) using homogenization. The pH was adjusted to 3 using 0.1 N hydrochloric acid. Dissolution testing was carried out in a hydrochloric acid medium using the rotating basket method. Particle size and morphology, FTIR, DSC, XRD, and surface area of the microcrystals were studied. The effects of drug and stabilizer concentration and homogenization rate on particle size and dissolution efficiency were studied statistically using a D-optimal design. The dissolution efficiency in both methods was increased about 3- to 4-fold. The particle size in both methods was decreased in comparison with untreated drug. Maximum dissolution and minimum particle size were obtained by the solvent-change method. According to the results, both microcrystallization methods are effective in the modification of the crystalline the habit of piroxicam.