Preparation and optimization of superabsorbent hydrogel micromatrices based on poly(acrylic acid), partly sodium salt-g-poly(ethylene oxide) for modified release of indomethacin

Abstract

The purpose of this study was to prepare modified-release dosage of indomethacin (IND) in the form of micromatrices based on a superabsorbent hydrogel (SAH), poly(acrylic acid), partly sodium salt-g-poly(ethylene oxide) (PAAc-Na-g-PEO). A soaking procedure was used for the preparation of drug-loaded hydrogel micromatrices. The amount of IND, volume of drug-loading solution, and amount of PAAc-Na-g-PEO granules used for preparing micromatrices were the independent factors. The dependent factors were the measured responses from micromatrices, that is, percent recovery, percent entrapment efficiency, and the time at which 63.2% of the drug was released (T_d, minutes). A three-factor, three-level full factorial design (33) was created to optimize formulations. Nonlinear regression analysis indicated a good correlation between the measured responses and the independent factors. Optimum responses were obtained from medium levels of IND and SAH and low level of drug-loading solution. Differential scanning calorimetry, X-ray diffraction analysis, and scanning electron micrography indicated that IND crystals are physically adsorbed into the pores and irregular spaces of the hydrogel.

Key words :

• Factorial design
• indomethacin
• modified release
• pH-responsive
• superabsorbent hydrogel

Acknowledgment

The authors are grateful to FARGEM (R&D Company, Duzce, TURKEY) for providing the drug and performing DSC and XRD analysis.

Declaration of interest: The authors report no conflicts of interest.