Background: Piroxicam exhibits low oral bioavailability, due to its meager solubility in water. The intent of this study was to ameliorate the bioavailability of the drug by employing a solubility-enhancing encapsulation technique.
Methods: Seven samples were formulated with piroxicam and gelatin using both solvent evaporation and electrospraying together. Evaluation of solubility and release rate in water and assessment of bioavailability in rats were carried out in comparison with piroxicam plain drug powder (PPDP). Other in vitro explorations were accomplished using powder X-ray diffraction analysis, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and Fourier-transform infrared spectroscopy.
Results: All piroxicam-loaded gelatinnanocontainers (PLGNs) enhanced solubility and release of the payload in water. In particular, a PLGN formulation consisting of piroxicam and gelatin at a 1:8 (w:w) ratio presented about 600-fold the drug solubility of that shown by PPDP. Moreover, 85.12%±10.96% of the payload was released from this formulation in 10 minutes which was significantly higher than that dissolved from PPDP in 10 minutes (11.81%±5.34%). Drug content, drug loading, and encapsulation efficiency of this formulation were 93.41%±0.56%, 10.45%±0.06%, and 66.74%±6.87%, respectively. The drug loaded in PLGNs existed in the amorphous state, as confirmed by X-ray diffraction and differential scanning-calorimetry analyses, and was more stable when analyzed by thermogravimetric analysis. Moreover, Fourier-transform infrared spectroscopy analysis suggested nonexistence of any piroxicam-gelatin interaction in the formulation. In the scanning electron-microscopy image, PLGNs appeared as round, smooth particles, with particle size of <1,000 nm. Amelioration in bioavailability of piroxicam with the aforementioned PLGN formulation was fourfold that of PPDP.
Conclusion: The PLGN formulation fabricated with piroxicam and gelatin at 1:8 (w:w) might be a promising system for enhanced biopharmaceutical performance of the drug.
Keywords: aqueous solubility; electrospraying; gelatin encapsulation; nanocontainers; oral bioavailability; piroxicam.
© 2020 Zhao et al.